Trinity - you are in no shape to do Draycote. Don't do it... not even "just" the marathon... Wait for FLM... You have many many years to go on to do more ultras in... as long as you don't turn your current injury into a really big one! (That's my advice anyway)
And I hated Mudchute last year... so I'm all for setting up another cheering point a little bit further on

)