Thanks for all the advice, I've just called BA again and explained the issue and that it's been going on for a month, so I put a thread on flyertalk and the suggestion was to call BA again and have another go....this generated a giggle but the nice lady said that she could see the problem, it was that a keyword wasn't copied into both bookings when the seat request was sent down.

So she seemed totally confident that it would be fixed within 2 days. Cross fingers...and thanks flyertalk for helping...