Halloween // Best shops for quality Halloween costumes in the UK?

Was looking at Doll's Kill's costume selection and they're all SO pretty and look like really nice quality. Then I realised it's an American based shop so if I'd need to return anything it would cost a lot of money. Does anyone know of any shops similar to this, or just good quality shops in general? I don't mind spending £60-70 but probably wouldn't go above that.