Looks like I did the right thing by using my points for my trip to the UK next August, while the "old" rate is still current. This will be my fourth points trip to London and, by the sounds of it, undoubtedly my last as well...
I've been amazed at how far ahead one needs to book, in order to take advantage of one's points.
Unless
Binos has got is sussed right, it won't be worth accumulating FF points in future.