[AB-UK]

I should think a civil court action against the dealer AND Volvo, on the grounds that the car was "not fit for purpose" should be on the cards here.

The engine of a £45k car, after only 25k miles, and regularly serviced in accordance with the manufacturer's recomendations, might reasonably be expected to last much longer.

The Judge in a civil case does not require definitive evidence since they operate on a "balance of probabilities" level, where common sense rules apply and I think any reasonable person would expect the engine not to fail in the circumstances you have described.

If you don't have a tame solicitor to hand, the CAB might be a good place to seek initial advice.

Which! also have legal advisors who as you might expect specialise in consumer law.

Keep us informed please.