Fortunately I can't afford a new/slightly used car on credit, I buy a car cash or don't have one, (hate finance companies), but whilst perusing the web (my partner had a car off yes car credit, I have just made a claim for refund of her payment protection insurance payments through this site), came across this link
Car Credit Complaints
In the forum, loads of companies get a mention, yes car credit, arnold clark, carcraft, hfc etc the list goes on, they all rip people off with loans and payment protection insurance (which many have claimed back), even toys r us get a mention!