Gareth - re Wilmington, it has got a long hill at the start, it's broadly an uphill first 5k and a downhill second 5k if I remember correctly. That said, a good few years back, I ran what was then a PB at Wilmington by easing off slightly for the long uphill and then really picking up the pace at the top of the hill for the second 5k. Don't know if the course is still the same, but it's a good race if you can handle the hills. I don't think the hills are any worse than Maidstone though.
Good luck with it.