Until he gets pulled at a VOSA checkpoint and they give him an unlubricated bumming with a pineapple.
Well....I suppose it could be legal....it has an over-run hitch - maybe he has fitted auto-reverse brakes, or plopped the freelander body onto a proper trailer chassis, but if he has just hooked it up to the standard drums and handbrake cables its not in compliance. Actually, it looks suspiciously like the standard mac strut suspension setup, so almost certainly non auto-reverse brakes. He is going to have a hard time convincing anybody it was build before 1980whatever the cutoff year is for home builds with standard brakes.