I have just set up my new router. Internet access OK. Wifi OK.

Working perfectly.

Where the new router is, I have two ethernet cables that run to different parts of our spread-out property. These run to additional wifi routers. I have used these cables and these routers for years, without needing any setup. I plug them in, and in those areas, they just work. 

I have plugged the cables into my new router. No internet access is sent to the additional routers.

I am trying to find them on my TP-Link control panel, 'Network Map' / 'Clients' page.

i can see two clients that are marked as 'LAN', and I assume that these are the remote routers? But i can't match any of the IP addresses.