After A Reasonable Time
If a fault appears after that nebulous "reasonable time" has elapsed,
don't despair. If it's in the first six months, and it's not because of
fair wear and tear, accidental damage or misuse, then the retailer must
still repair or replace the item. If he demurs, he has to prove the
item wasn't faulty in the first place, or that it couldn't be expected
to last that long. Often he'll choose to replace rather than repair it.
If more than six months have gone by, things change. You might still
get a repair or replacement, but now you'll have to prove that the item
was faulty when you bought it if the retailer disputes your claim.
Where delivery costs are involved, the retailer has to pay them, and
repairs must be carried out within a "reasonable" time. If it's
impossible to replace or repair the item, you can claim a refund of
some, or possibly even all, of the purchase price (depending on how
much the item has been used). However, if the fault causes personal
harm or damage (a fire, for instance), then it falls under "product
liability," which is the manufacturer's responsibility. First, though,
go to the retailer; if they're unable tell you who the manufacturer is,
then the liability becomes theirs.
http://www.consumerrightsexpert.co.uk/FaultyGoods.html