It's a fairly large two-car garage, with a single-pitch corrugated roof.
The price spread seems extreme, with the higher one being more than twice the lower. We're in the far north of Scotland, so there aren't many properly licenced businesses to choose from. Both are in the same town, so there's no difference in travel time.
I have no idea what sort of price to expect - any comments from people here who've dealt with this?