NFS:
Thanks for the info
The furthest i have ran before is a 10k but my current runners need updating as they are an old pair of adidas cross country which give me good support but thought I should buy a new pair for my half marathon since having the other trainers for about 7 years
Running shoes should ideally be replaced every year! If you do buy new shoes make sure you have a month to properly wear them in for the half marathon, you need your feet to be completely comfortable with them.
I got a Gel 1110 from Sports World about a year ago so they're due to be replaced soon, might check out the Gel Nimbus.