So full refund is usually only within 6 months then 6-12 is 80/75% after 50%
This is correct,
My understanding under the consumer rights act is ( if anyone else has better understanding of CRA 2015 feel free to correct me )
1. up to 6 months your entitled to a full refund or full replacement as it assumed failure before 6 months = manufacturing defect.
2. after 6 months it is up to the buyer to prove it was a manufacturing defect, however you should be entitled to a repair, replacement or partial refund.
3. The warranty that you get with the manufacturer has no legal standing and is offered only as goodwill.
4. Your contract ( under CRA 2015 ) is with the retailer, not the manufacturer so all correspondence should always be with the retailer. If they have their own RMA warranty contract with the manufacturers youll be out of the loop for that.
5. under CRA 2015 it is stated that goods sold should be robust and should last a "reasonable" amount of time. A gpu that fails in its warranty period I would suggest has failed the requirement of being robust.
The crucial thing here is how long has passed since the purchase.
if its still in warranty period then the minimum should be a fix, replacement, or similar ( 4070 ) or 75% refund. ( robust goods should last for ~6 years, so if youve had the gpu for 2 years then (6-2)/6= 66%, so a refund of 66% would probably be fair for 2 years of use.)
The final right to reject can only be exercised after "after one repair or one replacement, the goods do not conform to the contract;"
you can also raise a section 75 claim if you bought with credit card , for breach of contract.