All very sensible advice above. If you can get a 10 mile run under your belt before the race that would be nice as it's a good feeling to know you can get into double figures, but it's by no means necessary. There's a very good chance there will be people in the race who haven't run as far as you in training.
It's good to drink little and often, so you may want to experiment with carrying a bottle/water bladder. Or otherwise, take a short walk break at the water stations to make sure you get several swallows of water in at each one. You don't really need fuel for a half, but you could take a gel for a bit of a boost in the latter stages - or carry some jelly babies or other sweets if you don't fancy gels. But whatever you take, try them out on a couple of training runs first - you don't want any nasty surprises on race day!
Agree with Phil - there is a point where things start to fall into place. With me it was when I was able to run comfortably for half an hour - once I could do that, it felt much easier to progress. Running for an hour isn't twice as hard as running for half an hour. Your body takes time to warm up, and to adjust to exercise. Keep at it, build a routine so that your exercise is something that fits naturally into your day, not something you have to consciously organise, and soon it'll all fall into place.
Great day out at Race to the Stones on Saturday. Sunnier than forecast (I have ridiculous tan lines and brown knees). Really beautiful scenery - I recommend running the Ridgeway to anyone who has the chance. Caught up with Becca along the way and we ran the last 27 miles together - it was great to have the company, especially after it got dark. We were channelling Comrades - the aid station at mile 56 became 'Sahara Kingsmead Stadium' .
TB02 - I survived! Hot and sunny but spectacular scenery and a great race. I had vaguely pencilled in between 14 and 15 hours and was pleased to finish in 14:47 for a top 50 ladies' place. But goodness I'm stiff two days later - the hills have really taken it out of my hips and I'm still waddling like a penguin! 100kms is far enough, I think .