Thanks Ben. Funny thing is I decided yesterday to pull out. The injury is healing well but my physio recommended against that distance. To add to that, my aerobic fitness has taken a hit and I don't think I would be able to complete the distance without a real struggle.
As someone else put above, I think I'd like to do myself a little better justice than that.
I've contacted Challenge Running and will be running Stort next year. I still hope to get my first ultra in next spring and meanwhile am aiming for a half to finish this year off.
I wasn't injured for the marathon, but training hadn't gone brilliantly for the last week or so, due to a cold. I had been hoping/training for closer to 4:30, but decided - as it was my first - to just enjoy it and make sure I got round.
I think I agree that I would be pushing my luck to try for the 30 so soon after a forced break. I think I just wanted to hear it from someone else, so I didn't feel quite so much like I was copping out, especially after a couple of other DNSes earlier in the year.
Thanks for all your feedback. I'll probably set myself a Half to aim for before the end of the year and then restart and aim for my first ultra next spring.