Then I suppose it works as DAC-Amp and would require a direct connection between your streamer (Nucleus) and the Devialet. Or you must set up some Roon Bridge device which can receive Roon’s signal via WiFi and connect via USB to your Devialet. This could be as simple as a Raspberry Pi with RoPieee.
I wish you good luck and happiness in your new home.
I am getting even more confused now 
I do not need a Roon Bridge as I have the Nucleus
I spoke to the developer today about this issue and I am apparently the only one who has asked to have their Router in their main living room…really!!
Anyway they are looking into it for me .
If they dont come up with a viable solution I may get a Disc extender that I can hardwire the Nucleus into
Your Nucleus is your core. You want to install it in your hallway, or that was your last idea.
Roon core will stream to any compatible Roon endpoint it encounters on the same network. This may be a Roon Ready device connected to the network, or a device with Roon bridge software installed. It’s also possible to stream using other supported protocols like Airplay, but that cannot be what you are looking for.
So, as your Devialet is not Roon Ready and doesn’t have Roon software itself, it must be either connected directly to the Nucleus (e.g. via USB), or its must be connected to a device which runs Roon bridge software. Doing this, your Core will stream to this device with Roon bridge software, and the device will output to connected DAC (USB, S/PDIF).
As your Nucleus will be in the hallway and cannot be USB-connected to your Devialet in another room, you must provide for a device with Roon bridge software.
Your situation really is not unusual nor is it a big deal. I already told you that if it were my decision to make, I would have the cable installed. This is most probably easily done. That said, I too have my Roon core connected to my router and my DAC in another room and didn’t want to install a cable, because I also am looking forward to a new home and will not be much longer at the present place. So I opted for the second best option - I got me a Raspberry Pi4, installed RoPieee (Roon bridge), connected the Raspberry to my WiFi and my DAC to the Raspberry. Works very well for me.
At my new home I will make sure to have cable installed.
Yeah the cable seems the sensible option, but its messy . I will have a good think about my options
I disagree that I need a roon bridge as my Devialet can stream wirelessly from my Nucleus if the Nucleus is hardwired.
Cable seems best option though I agree, I will consider wifi disc if this would allow me to hardwire the Nucleus and be able to have it in my living room.
Thanks for all of your input, much appreciated
Steve
You were 36£ away from a simple, straightforward solution (albeit temporarily for ´looks´ reasons.
Just putting a power plug into the wall plug, 1 ethernet jack into the router, 1 into the switch, and you are all set to connect ALL networked equipment in your living room.
Time enough after that to start tinkering what the final, ideal solution will be, all whilst enjoying your music.
Do not complicate your life that much
Dirk
Brother, you’re overthinking this.
Hire an electrician to run Ethernet from wherever to wherever. Add a switch where it’s needed.
Don’t know why you would want a router in your living room, since they are seldom touched once setup They are usually placed in out of the way locations (e.g. a cellar or closet), but whatever.
I am an overthinker by nature, combine this with the lockdown and its BIG trouble 
Yes I think I will get an electrician to do what you suggest. I may take a temporary solution at first but as its a new home development they will have electricians on site so will ask them.
One question the Netgear or TP Link switches , does the router just plug into one of the ports like the other devices would?
I don’t know your setup, but generally, there is a cable of some sort coming into your house that carries the internet signal. That cable plugs into a modem or a modem/router combination. You can have that located anywhere you want it that makes sense. Just have the incoming cable pulled to the appropriate place.
From your router, you can connect devices using ethernet cables or WIFI. If you need more ethernet connections than your router has, you can put a switch there to provide more ethernet connections.
Roon recommends your Roon core be connected using ethernet, not WIFI. This is because there is a lot of data moving from the internet to your router, then to your Roon core. From the Roon core a lot of data moves back to your router and then to your Roon endpoints and Roon control devices.
Your Roon end points can be connected by WIFI or ethernet, but ethernet generally works better. However, in many/most cases, WIFI works well for connecting Roon endpoints.
Depending on where your equipment is located, you probably don’t want multiple ethernet cables running from your router to your Roon core and/or Roon endpoint devices, etc. You can simply run one ethernet cable from your router to this location and install a switch there. Then use two or more short ethernet cables from the switch to your devices.
In addition, you may want to use a USB or HDMI cable from your Roon core device to a Roon endpoint device. In this case, you would normally want your Roon core sitting close to your Roon endpoint. However, if you don’t need a direct USB or HDMI connection from your Roon core to your Roon endpoint, you can put your Roon core device anywhere in your house that has an ethernet connection available.
Yes, any port will do.
But to keep it ‘structured’, just select the 1st port (numbered either 0 or 1 depeending on switch) for the router connection
Dirk
And by the way, you can test this already at your place right now (if you buy the equipment of course)
Dirk
Just to sum up
I am asking the builder if I can somehow get my BT internet connection into my living room so the router can go in there.
If not I will probably go down the cable run and switch route …hopefully as tidy as the electrician can make it
Thanks for all the help , some great responses
Yes, ethernet cable running through the wall (or however) from the living room, or any other rooms, will simply plug into the router, in one of its ports.
For example, I have a modem & router in a back of house cabinet along with a separate 16 port unmanaged (dumb) switch, which plugs into the router. Then I have ethernet wiring running from most rooms in the house back to that cabinet. Those ethernet cables plug into the 16 port switch. In each of these rooms (where I have endpoints for music, TV, etc.) I sometimes plug the related item into the single ethernet plug in the wall plate. In locations where I have several internet connected items (stereo cabinet or TV location), I simply have another unmanaged (dumb) 4 port switch. The switch plugs into the wall plate, and then I have 4 ports for equipment at that location.
As @xxx suggested, get an electrician in there, and do it now. Explain your needs to the builder, emphasise that it’s likely WiFi in general won’t cut it, and let them come up with a solution. It’s their job to figure it out for you, so make them get it done.
It might be that your BT connection comes through a fiber line, and that for some reason, that’s more of a pain than doing a few drops of RJ45. It will be essentially invisible, bar an RJ45 wallplate somehere.
Hardwiring your home is completely doable and shouldn’t be horrifically expensive, especially if you do it before everything’s finished. If you do it after it’s done, there’s finishing that might need to be redone, but it probably still isn’t a huge deal.
You probably want them to use something called CAT6a cable for future-proofing. Ideally, you probably want a couple of those RJ45 jacks per room. Another nice perk of this is that you can use proper, Powered-Over-Ethernet, extenders: hubs that are hardwired to a switch, itself hardwired to your BT router, and which will give you the best WiFi signal you’ve ever had, everywhere in the house, without the compromises that come from Powerline or the spectrum-sharing of mesh wifi. These also exist as in-wall units.
If you have carpets you can always hide the cables tight up against the skirting board next to the gripper.
I would run both a network cable and telephone cable, if you have FTTC ADSL broadband you may want to change between a separate modem and router rather than just a combined modem/router at some point.
Just an update to everyone who contributed to this thread.
In the end I have decided against a wire run and the other options.
I have elected to use the BT WiFi Extender 600 . So far this is working with no real issues.
Thanks to all who posted on here.
I am back again, nothing is simple with this hobby 
Ok so I have the connection to Nucleus I require but my Roon remote on my Ipad is affected. It may be a coincidence but I doubt it.
So album art loading very slowly , it even loses the Roon Core on occasions…this is only for a few seconds.
If I am playing a full album its no bother but if I skip a track or I am browsing Roon it has become very very slow, to the point where its too slow to enjoy. I will stress this is only when using TIDAL, when using and browsing my own library it works flawlessly
Would the new Wifi extender cause these issues?
I have 9 devices connected to my wifi according to the BT app. Is there any way I can find out what they are. Some are clearly named but four are unnamed. I was thinking if I find out what they are and disable them , it may help.
Any advice as always appreciated
An iOS appp called Fing will tell what device you are using.
Unclear from your post whether you are using any Ethernet or if it’s all WiFi.
The Nucleus is the only device using Ethernet .
I will look at the above app thanks
I like the ping app but it does the same as the BT APP , three of my devices are labelled generic, I am keen to find out what they are .
Although to be honest I don’t think it will make a difference to my roon app reliability