Car on finance or bank loan?

I have around £1,200 left to pay on a car loan my mother took out in her name which i have been paying over the last few years.but i am looking to buy a new car in the near future.if i took a bank loan, i could use some of the loan to pay off the money i owe my mum and use the rest to get a new car.but if i take out finance on a new car, i will still have the rest of the money i owe my mum to pay. although i heard that places like arnold clark will write a cheque to pay off what you owe on your old car - something i would like to do.what do you think i should do? visit the bank or go with a dealer and get finance.
Answer
Bank or places like tesco, they charge about 6.5% interest, they are far cheaper than car finance which is about 15% if not more.