Have had all sorts of broadband problems so have been using old 582n in master socket for diagnostics. Managed to get plenty of data using routerstats which should help my case but after the line dropped this afternoon the connection was terrible even though it never dropped again - varied between slow and stopped. Disconnected the session and reconnected to no avail so went for reboot. This took much longer than ever before (about 5 minutes) and I can no longer connect to it. The wifi light is also solid red.
Back on the trusty TP-Link connected to extension upstairs and everything seems fine.