I disagree, TG is too much of a ratings winner for the BBC. It was the Hamster's car accident that caused the ripples, so I think the Beeb will revisit how the show manages H&S but that its future is secure.
If squatters are in occupation, the easiest way to reoccupy is to get in while they're out. However, experienced squatters get round this by always leaving someone in the house.
I would consult a solicitor. Sounds like a rough part of town tbh.
I'm sure if you give reasonable notice, you can remove the vehicles. Or write/email the guy stating that if he does not remove the vehicles within say 14 days, you will assume he has ceded legal ownership to you.
Worth seeing what the DVLA have to say as well.
Could it be the new vehicle that they're deploying for combat troops in Afghanistan? I haven't been keeping up with developments...which is rather slack of me.