hmmmm as far as I can see it has ~sort of~ sorted the problem. I still get the auto-disconnect message about 20s after joining and then I just reconnect, but the internet doesn't go down in the house, which is good!
I have been getting exceptionally choppy frames (200-300 when no one on screen, down to 30-40 at the worst, 90 ish with pretty bad lag with people on the screen - pipes teleporting into me and other things) and some massive lag spikes (sometimes approaching 800 ping). When I played at uni I used to get 200 frames pretty constantly and when I practice offline I get this too. Would it be egregious of me to blame this all on the internet?
Thank you for your help so far!