I tried all the vatiations (dhcp, no IP and gave it and IP) but no joy. I tried a couple of variation on the MTU settings, the one that BT suggest and the one that the modem picks up when I run the wizard. Doesn't seem to make a change.
You might have more luck with the FTTC, this is conencting to ADSL 2+ through a modem, unfortunately, fibre hasn't made it to my parents house.
I should say, ingnoring some DNS issues, I did have it working with Plusnet ADSL in the same configuration (different pppoe settings obviously). There's no reason it shoudln't work so it's really perplexing.