Hi I've tried delilahs and may have to wait (always a good sign I know) but our conversion inside is taking place throughout March and early April and they can't do until May.... And other suppliers of the bed who can supply fully upholstered too???
Buy bed, buy foam, get upholsterer to cover. They don't have to be a dub specialist, it's just upholstery...
Kens Customs did ours..brilliant guy, highly recommended by a few on here. http://www.kenscustoms.co.uk/
As a pro auto trimmer I have to point out that trimming is definitely NOT just upholstery, that is if you want a professional and long lasting job. Different techniques, different threads, different materials. Get any of these wrong and it wont turn out good. Ive seen many auto trim projects attempted by sofa upholsterers and tbh its embarrassing!