If anyone is looking for an alternative to London, I highly recommend the Brighton Marathon. Entries are due to open on Monday 10th May and it is expected to fill quite quickly. 

This year they allowed people that gained entry into London to defer their places, and I would expect them to do the same again next year.

I'm planning on entering it again, as it was a thoroughly enjoyable race (apart from those last 5miles! ) and the crowd support was amazing.

Shaun