Steam in-home streaming - any advice on setting it up?

[#1]

I've just recently moved to fibre and a new Plusnet Hub One router. I'm trying to get Steam in-home streaming working but neither my desktop nor my laptop are seeing the other computer on the network. I've managed to get it working previously on different PCs and using different routers, but not this new router.

Steam needs both computers to be on the same network and subnet and to have UDP port 27036 available to the app (and it doesn't seem like it can be shared with other apps). Both PCs are running Windows 10 and have static IPs in the 192.168.1.x/255.255.255.0 range (DHCP server is running on my NAS, not the router, as I have more control over it that way). I think that if I can get the UDP port open, it'll probably work, but I can't see how to do that with the Hub One.

I've looked in the router's Firewall settings, specifically at the port forwarding options, but that doesn't seem appropriate: a rule set here is for internet traffic, not intranet, and would only open the port for one computer anyway, which clearly isn't useful when two-way communication is required. Does anyone know how to get Steam in-home streaming working, either by changing settings in Windows or in the router?

Thanks in advance. 

*Edit* The desktop PC is connected to the router via a powerline network, the laptop is connected wirelessly.

[#2]

Could be a Windows Firewall issue, try disabling it on all 3 devices to test before re-enabling.

Also, you may find that using powerline networking can add quite a bit of latency to game streaming. My friend was using it for his Steam link and said it was pretty bad. He changed to using an actual network cable and it fixed the latency. Just something to keep in mind.

[#3]

The laptop's a Microsoft Surface: no wired ethernet without a dongle, which I don't have. The powerline network and use of wifi will both reduce performance, but are unavoidable: I'll live with the consequences because I'm only really testing this out rather than expecting to make significant use of it. I've tried disabling both the Windows firewall and the protection settings in my antivirus software (BitDefender Free) and the PCs are still not visible to each other, so I strongly suspect that the router is the problem.

[#4 · Accepted solution]

Did some more googling and it seems that the problem is caused by the presence of virtual ethernet adapters on one or both of the PCs. I've got both VMWare and VirtualBox installed on both PCs and once I'd disabled the adapters on the Surface, it became visible to the desktop, and vice versa. Now I've just got to work out why most of my games won't actually launch.