disputing damages to a voluntary return of car

[lescon]

Hi I am after a little help my daughter got an offer of a job in Australia so had to voluntarily return her fiat 500 62 plate pristine condition only 9000 miles. we had to have it collected as we were not allowed to deliver to our nearest Manheim auctions dont know why! Three gentleman came where two of them inspected the vehicle with a vehicle condition report. They picked up on some very faint scratces to rear bumper hardly visible to naked eye. I said that this should be classed as wear and tear they assured me that that was most definitely the case but every defect had to be logged. Everything else was ticked and no other marks recorded to the vehicle condition report. This report i signed and so did the inspector. They had to then drive this ar after a lot of arguing as none wanted to drive a bright yellow car back to Glasgow. Five weeks later we get a final bill and they have charged £464 for damage to left sill. They sent me a pic and it was very visible. I told them this was not on the car when it left our property. i said the left sill had been inspected and ticked. They said the condition report was not an accurate it has a more detailed check back at the auctions. Surely this cant be right as i had to witness these two men inspect the car and as i say thesy noticed scratches to back bumper hardly visible to naked eye yet they did not notice a dent and paint down to metal in left sill. Please i do not know what to do i do not want my daughter having to pay for damages that must have happened after leaving our property. Any help appreciated.