Under sale of goods legislation (Sale of Goods Act 1979) consumers are entitled to expect that any goods they buy are of satisfactory quality. That is, that the goods meet the standard that a reasonable person would regard as satisfactory taking into account the way they are described, their price, and any other relevant circumstances, such as the fact that they are second-hand or used.
Matters which should be considered in assessing whether goods are of a satisfactory quality are:
• whether they are fit for the purpose for which goods of that kind are commonly supplied, or fit for any other specified purpose;If a product that was not of satisfactory quality at the time of the sale is returned to the retailer, the buyer is entitled to a full refund (if it is within a reasonable time of the sale), or, if a “reasonable time “ has elapsed, to a reasonable amount of compensation. The consumer needs to demonstrate the goods were not of satisfactory quality at the time of sale. This is so if the consumer chooses to request an immediate refund or compensation. It is also the case for any product returned more than six months after the date of sale.
There is one exception – this is where the consumer returns the goods in the first six months from the date of sale and requests a repair or replacement or a partial refund. In that case, the consumer does not have to prove the goods were faulty at the time of sale. It is assumed that they were. If the retailer does not agree, it is for the retailer to prove that the goods were satisfactory at the time of sale.
Any legal proceedings to enforce a claim must be started within 6 years of the date of sale.
• whether they are of satisfactory appearance and finish and free from any defects;
• whether they are safe and durable and as described.
copied and pasted from og's link.
Where it says " within 6 years of the date of sale " that is 5 years for Scotland.