Hi Mark,
Yeah, was thinking that may be the case.
All of them who have turned up have said it's an easy enough job as the garage is only about 6 years old, complies with buidling regs for the structure (not insulated, but cavity wall, proper roof trusses, pitched & tiled roof etc), even the electrics were inspected and signed off against.
Pretty straight forward as far as I can; bathroom, bedroom and one open plan living space with a kitchenette.
Yes it needs fully insulating and a couple of stud walls putting in, but nothing out of the ordinary.
Will see if any come back in the next couple of weeks (not looking for it to be started this side of Christmas) but if they can't be bothered to come back with quotes when they say they will you start wondering about how they'll be when it comes to the job!
Cheers.