Thanks, Nick, I think I'm taking the airwaves over here
Since I posted the question on the forum I have indeed joined Freeserve Anytime, and will go Broadband with them if BT ever get their finger out and add that extra one to our registered number on the trigger level. I'm sick to death with BT, and never get a satisfactory answer to any queries.
I haven't called the help line (it's in India now, isn't it?) and have only emailed them. They seem to stick to certain answers without deviation, repetition, or hesitation (and I hate Just a Minute, too!).