COMMUNITY DISCUSSION Used cars
England & Wales used car: what should I keep if I need to complain?
Keep the advert, sales invoice, payment record, finance agreement, warranty, MOT/history checks, messages with the seller, photos/video of the fault and any diagnostic or repair report. Those records can help show what was promised, when the fault appeared and what remedy you requested. Guide: https://getinstantlaw.com/uk/england-wales/used-car-problems
Community posts are personal experiences and general discussion, not legal advice. Laws and procedures depend on jurisdiction and individual facts.