What’s a fair depreciation charge per mile when returning a secondhand car to the sales garage? I bought a 10-year-old Skoda with 78,000 miles but, after 6 weeks, it was obvious that the engine was shot having been badly looked after. The garage says it will take it back but wants to charge 45p per mile depreciation - which seems like they’re having a lark. How can a car that cost £4500 with 78,000 be worth only £3500 at 80,000 miles? It seems like they want to charge me with an engine rebuild. Any thoughts? Am I being taken for a ride here? Thanks for any advice.