Thanks for the info, folks; I suspected there was no easy hack (as yet) to make the BB2 more cooperative. I've had an 8800NL for 12 months on ADSL2 and it has been probably the best performer, in terms of sync rate/stability/low-errors, of the very many routers I've tested. On VDSL it also performs excellently, high sync, no bit-loading decay, low error rates, and it is my router of choice. The BB2 performed as well as the 8800, at least over a couple of hours, whereas an unlocked HG612 gave a 10% dip in sync rate (over 2 separate test hours)......the advantage of the BB2 would have been its low cost!
In view of the advice, I think I may treat myself to the suggested Zyxel to see how it does.........though I've no need for wi-fi, being entirely ethernet based ( if anyone visiting needs wi-fi, I switch on an attached Netgear WGR614 for them).
I think maybe the BB2 could suit Talktalk users as well as EE, as I have noticed that Talktalk seem to allow non-Talktalk usernames - I helped one chap whose router I found had been set with his Gmail details, and had worked for years like that! My own test router worked straight away using a made-up ISP account. I wonder if there are any other such 'relaxed' ISPs?