TT have nothing to do with Plusnet - Plusnet is linked to BT. Their call centre is in Yorkshire which some find easier to understand than India!
Don't have it myself, but seriously thinking of changing when fibre optics become available here. People I know who use Plusnet seem happy with the service (with one exception who had endless problems with email. He's gone back to BT despite me telling to just setup a gmail acct!).