I asked an AA staff member to send an email to Mrs Weaver with some advice about the feasibility, if any,of changing over from the units-based tariff to one of the (Home|SoHo)::.* deals.
This is despite the fact that I have a multiple bonded line set up and need combined quota over the n lines. And I want to retain my existing good things - (1) IPv4 address block, foc, (2) BT “Premium” traffic prioritisation (it used to be called IPStream Max Premium iirc, something like that, not sure what it's called now?) and (3) BT posh repair/call-out thingummy [cant remember what it's called - ".* care"?], on one line.