The forest is pretty soggy at the moment, it has to be said. I think pretty much all of the "off-road" is gravel track, so shouldn't get too muddy, but, like DianaD, I don't remember the ford, and I imagine that will be pretty high now.
I still haven't trained up to 10M this year, and so rather than the PB which I was determined to go for after last year's PB on this course (71 mins 9), I'm going to say I'll be pleased to get in around 75, and not disappointed if I'm under 80 mins. But I don't know if these are realistic times.....
I would think you could find somewhere to leave your bags, as there are plenty of tents/ buses/ mobile cafes there, so if you talk to the organiser, you should find something.
I did this one in 2005 - it was scorchingly hot - although i'm not sure we're going to have that prob this year - and hilly, but a beautiful course - and I'm probably going to be back this year. It's the only half I've done, so can't compare PB potential (would have thought it's too undulating). It's a small event though, so the field gets a bit spread out - I think there was one point where I could have gone either of two ways, and couldn't see a direction marker!
Having said that, overall was a very good experience. Worth doing - you'll feel you've acheived something!!