As long as it's an HP agreement and not a PCP, once you pass the point of 50% you can hand the car back with nothing more to pay as long as it isn't damaged. But the sums are £10,000 + £7,200 a year for at least 3 years (£31,600, maybe more), which means she can't be far from paying it all off. An 06 basic 400h still trade books at £18,775, so I think she has more equity in the car than 50% and it would be foolish to throw that away.