Faulty Used Car from a Dealer

Dealer sales: goods must be of satisfactory quality, fit for purpose and as described (Consumer Rights Act 2015). If a car fails these tests you have a short-term right to reject and get a full refund within 30 days, counted from when ownership, delivery and any installation are complete (s.22). source

After the 30 days you can ask for a free repair or replacement; the trader normally gets one attempt, after which you can claim a price reduction or the final right to reject (s.19). source

For the first 6 months a fault is presumed to have been there at delivery unless the dealer proves otherwise; after 6 months you must show the fault was already present (s.19(15)). source

For motor vehicles the dealer may reduce a final-right-to-reject refund by a deduction for your use, including in the first 6 months, which is the exception to the general no-deduction rule in s.24. source

If you buy a car at a distance (online or by phone) from a dealer you generally have a 14-day cancellation right under the Consumer Contracts Regulations 2013, starting the day after you receive the goods; you have a further 14 days to return it. There is no automatic right in a showroom purchase. source

Section 75 Consumer Credit Act: if you pay by credit card (or buy now, pay later) for an item costing over 100 pounds and up to 30,000 pounds you can claim from the card provider for breach of contract or misrepresentation even if only part was paid by card; chargeback may help with debit cards. Escalate to the Financial Ombudsman Service if refused. source