I think this thread and numerous other ones I've seen on AAM over the years point to the confusion that can arise regarding consumer rights and what consumers think their rights are.
As I mentioned in an earlier post, the legislation in this area was updated and consolidated last year, but I would suggest its still not clear for the average punter - thanks in large part to our common law system (INAL but have had some limited experience in this area).
The new Consumer Rights Act 2022 in Section 17 and 18 lays out requirements for what state the goods should be in and refers to their durability, reference is also made to spare parts and after sales service for a reasonable period but then is unclear on what a reasonable period is!
In this particular case where a product has been received and used for a number of years, the onus is on the consumer to show there was a defect existing in the oven rather than the damage being as a result of wear and tear or other accidental damage.
The six years that is very often quoted, I believe, is linked to the Statute of Limitations Act 1957 Section 11, which states an action arising from a simple contract must be taken before the expiration of 6 years. So if you believe you have a case against a supplier you have bought something from you have 6 years from discovering the issue to take that case with the onus on you to prove that case. This is not strictly a consumer right.
I certainly don't expect my underpants to last 6 years!
So on that basis if EarlyRiser's underpants disintegrate after the first wash and the shop is refusing to play ball with him, he potentially has 6 years to take a claim against them! Still not sure I'd want to turn up in court with them though.