I wanted to say how pleased I am about the new changes. I had flights LGW-GVA booked ages ago (May I believe), family of 4 in J, using a 2 for 1 (I know - what a waste, but with young kids we could see no way of using it for long haul).
I rebooked under the new system, slight change on flights (return leg was 2 hours earlier than previously booked - but no big deal). It cost me an additional 18000 Avios, but I got my 2 for 1 returned and I will get £150 returned (including allowing £60 for the cancellation fees).
So....I get £150 and a 2 for 1 (valid until Feb 2013 - maybe I can persuade Mrs. Gate to travel long haul without the kids) in return for 18,000 Avios. Seems like good value.