Thanks for the suggestions - plenty to think about!
My exisitng UK bookings will take me most of the way to meeting my targets. If I also get the globetrotter target, that unlocks 26,400 points + 23,000 achievement bonus. Origianlly I was going to leave it, because I've already got 2 foreign trips planned but didn't see the point of 2 international mattress runs. Now I'm considdering it