[Will]

If he charged you VAT and he's not registered for VAT, I'm pretty sure that comes under the fraud prevention act. You could simply report him to the police, and they will take it from there and the courts will force him to pay your money back.

Or if you're not feeling that vindictive towards him, you could phone him and threaten legal action. He then has the option to pay you back the money; after which you should report him to the police anyway.

I doubt he makes enough money to warrant paying VAT, so I doubt he's planning on registering any time soon, and will go on to continue to con people out of money.