Almost certainly wiring - I have a similar issue. The house has been rewired piecemeal - room by room as we do it up. Probably a mistake in hindsight - but too late now! This has left one room with very old (1960's) multi-strand mains wiring, which is apparently not good for powerline networking. Modern single solid core wiring is much better. Unfortunately this is the room with most of network connected computer kit! Struggling on with a Wi-Fi solution for the moment, but will be fixed when we get round to the renovation.
Demon dial-up ('97) > Freeserve dial-up ('00) > Zen 512 ('02) > Metronet PayGo 1000 ('04) > Newnet Home 2050 Lite ('05) > Home 8050 Lite ('06) > Home 8050 M ('07) > back down to Home 8050 Lite ('07) > Be Value > ('08) > O2 Standard ('09) > Orange Broadband and Anytime Calls ('10) > EE fibre broadband ('16) > ?
Edited by TheLastMan (Sat 07-May-16 16:08:43)