I've just purchased a pair from Wiggle as they've got a pretty good sale on, they've arrived but I've yet to try them out.
Since they've arrived I've started to read such things as gait analysis and it seems Moti and Run and Become in Cardiff offer this service, so it might be worthwhile heading to one of those shops for free analysis to ensure you get the right style of shoes for your feet.
As fas as I know this service is free if you purchase the shoes from the shop, might be best to confirm this before hand though.