You are legally obliged to tell your insurers of any material facts. It
would be wise to do that before buying. Personally I would walk away from
the deal.
If he's found the right house in the right place and the only defect
is that the garage legalities are a bit complicated I think he'd be
mad to walk away
Anna
~~ Anna Kettle, Suffolk, England
|""""| ~ Plaster conservation and lime plaster repair
/ ^^ \ // Freehand modelling in lime: overmantels, pargeting etc
|____|
www.kettlenet.co.uk 01359 230642