Sorry - no that is not issue and my fault for bad / lazy use of language. The Velop actually feeds a managed switch.
I think the use maybe that it is a managed switch as per this article Linn Akurate DSM disappearing from Roon after installing new Ansuz Acoustics network switch but wondered if there are any settings that I would have to change for my router in this instance.
I have also ordered a non-managed switch to see if this is causing the issue but my future roadmap has me using managed switches so I would be partly regressing my doing this. Any help on the managed switch or any other ideas most welcome