Slowboy, entries are possible on the day if there are spare places; the details specify a limit of 500, but don't know how popular it is.
It's only £8 and that includes a T-shirt, and as far away from a concrete jungle as can be imagined.
SB, sorry you can't make it when you're in the UK. I was quite tempted by the Great Scottish Run but it'd be a long day out so...Are you seeing Drew there?