what you do is ask the seller to get a settlement letter from loan bank.
then double check that the loan details on the letter are related to the actual car you want to buy.
then on the day of the sale, you get two drafts, one in the amount of the finance and you lodge it into the bank yourself in the company of the owner (that way you know 100% the HP is being cleared), then give the balance of the sale price (the other draft) to the seller.
now the cars yours and your 100% happy that the finance is cleared.
hope that helps, i dont the same thing in Dec 09.