Thanks for the responses so far.
Plodding Hippo, I'm also gutted at the Abingdon marathon being cancelled, so it looks like Luton in December to do my 2nd marathon.
Selfish Git, Back to back marathons is a tad extreme, best of luck. In regards to the wife being faster, It's good, because she can get me my drinks and clothes whilst she is waiting for me. I may have lied about that but it sounds good.
Cougie & XL-man, sounds like a plan to target one of them, but at the same time you only live once, and Wycombe's start is very steep to say the least, so the extra effort may well be in MK.