Re the original post - We opted for Devons and never looked back! Though very similar to the Sussex which you'll have plenty of nearby I'm sure. You could do a lot worse than go meet and chat to breeders near you. Personally I'd steer clear of Dexters, though they have their fans on this site!
Ease of handling with no facilities was the main thing, tough yet quiet - Started with a couple of in calf cows on a welsh hillside, out-wintering in a shelter, TB tested behind a gate (actually didn't even need the gate!) and scanned standing still for a bucket of food - Greed counts for a lot!
Rearing calves is a doddle once you know what you're doing, but need plenty of air, cleanliness and a vigilant eye for being off colour...
Keep us posted!