Hi SunKing,
My husband has informed me that when you buy anything privately, you don't have to pay VAT. VAT is charged by businesses who make more that £47,000 a year. So, yes you would pay it if you bought from a dealer, and no if from an individual.
On a side note, they do have car tax here, kind of like the tax you pay each year back home when you renew your car tag. You can either pay it once or twice a year. If you do buy privately, it's worth it to check how much time is left before the tax is due again for the car and to be sure it's reflected in the price if it's up soon.
I hope that helps.
Jenninberks