Did exactly what you said here. Still wouldn't load anything, wiped everything, tried again, still nothing.
FINALLY found this:
https://www.tvaddons.ag/uk-broadband-users/
And realised I wasn't doing anything wrong, it was BT's "smart setup" that was causing me trouble. Disabled it, now everything works!
Going to wipe and just install the handful of things I want on there.
Phew, about punched my tele in.