We were thinking of sacrificing some of the garage space under the house to make into a new bedroom for visitors/spare room use, but now we're thinking of getting one of those tiny home type things in the garden for when we have visitors, and also could be used as a kids retreat when they are older, and maybe a home office if required too. Could possibly AirBnB it too, so there's a lot of possibility and it's also likely to be cheaper and quicker than messing about with the garage.