There's Jandaz in Wales too (not sure which bit and therefore how far it would be from you, but Romeo on here is Janice from Jandaz so try sending her a personal message).
I've never heard of a rescue Cockapoo in the UK. I'm sure there must be some, but as Cockapoos are nowhere near as common over here as they seem to be in the States, a rescue cockapoo is probably a bit rarer over here (and probably would be simply described as a cross-breed rather than a cockapoo). I'm sure someone will correct me if I'm wrong on that, but I trawled rescue sites for months when trying to persuade my husband to agree to a dog and never came across a cockapoo.
Let us know how you get on!