Many ex-lease or ex-rental cars may have been first registered to odd-looking companies. My Pug 207 came from a Peugeot dealer but spent its first 13K miles 'owned' by a dormant Securities company. It looks strange but it need not be a worry. Dealers will prefer not to 'own' a car for a period which may only last a few weeks before it is sold. You seem to have checked the important points.

Its listed as one owner however when looking at the V5 document the name it belongs to is an autolease company, and apparently the garage he works at brought the vehicle they have used it for two years done about 16k miles but haven't changed ownership of it, because they didn't want to increase the previous owners.... everything else checks out, the cars lovely but alarm bells are ringing....

Has the garage used the car from new? If they haven't had it from new then this is ringing alarm bells with me too.

If the garage acquired the car as a used buy, then they should have registered the car in their name (before using it for 2 years). Garages don't register cars in their name to sit on the forecourt, but they do need to register it before using it for anything other than test drives.