I assume you mean Dumfries (flying further away to hire a car doesn't seem sensible to me :)). Glasgow is nearer, though that is only marginal. It's only just over the border, nearest habitation is Carlisle. It was 6 hr drive from here when I checked, 1and a half from Glasgow which with getting to the airport etc is not much different, cost wont be that different either. If you want to fly to Derby, it's east midlands you want, about 30 mins away.