ITS WORKED!
okay so I setup port forwarding on the BT Home Hub
I created a new “Game or App” called Google Nest
I selected the “Google Nest” app and as a device I put the IP address in 192.168.1.230
I then setup forwarding for both
55000 <> 55000
46685 <> 46685 << this is the port specified in Roon Arc
and it has worked!
I have a feeling the port in Roon is going to change so may need to look at this again.
I might be able to enter a range eg 45000-55000 <> 45000-55000
thanks for everyone’s help