There are a bunch of links you'll find from google on uk consumer law. I included some below. I'm not an expert, but I did successully remind Canon UK of the law when my 100-400 failed three times in a row. And then they lost it. I had to go as far as a small claim in the county court in order to get their attention. Not particularly nice.
There are several laws which apply here. It's worth finding out the names and dates if you need to use them. You can get free legal advice (and you won't be able to recover legal costs); ask at your CAB (links below).
Let's say you buy a camera from a retailer with a credit card. If it goes wrong, then you have redress against credit card company, retailer, and the people providing the warranty.
If it's DOA, then you can argue that it was not fit for the purpose it was sold for and ask the retailer for a replacement. If they don't give it to you, then publicise it here and talk to the credit card company. The CC company will issue a chargeback at your request (they don't have a choice). The retailer is then out-of-pocket by the amount of the purchase, and they must recover than cost from you, if they think they can. Of course as the thing didn't work, they will be unable to do that. Game over. Buy a replacement from somewhere else. It's unlikely to go this way as the retailer doesn't want you to issue a chargeback (mention it to them and see the effect) because that leaves them with a cost which is really the supplier's fault.
In the case of my lens, the thing failed after a month and they said they'd fix it. It clearly wasn't DOA, and I thought it reasonable to allow them to fix it. By the time it'd failed three times and been fixed twice, they finally lost it. I was a bit fed up with the retailer and Canon UK by this time. Taking advice, I could have issued a chargeback, but that would hit the retailer first, where as actually it was Canon UK who had lost the lens (they tried to suggest I'd lost it, but the receipt I thoughtfully extracted from their courier said otherwise). I was advised to sue Canon direct as the simplest approach.
I got a claim form from the court service (below), and filled it out. The court service will even check you've done this correctly. It's much easier than a few years ago (when it was a "pliant" form). I sent a copy to Canon UK explaining that I'd file it at such-and-such a time if they didn't get their sh*t together. Lo and behold I got a call from a competent lady from Canon UK who appeared to understand the pain they had caused me. She certainly understood that I was going to win. We negotiated and I got what I wanted within 15 minutes. Not surprising when you think that it would cost them several times the value of my claim (1500 quid) to defend it, and they would lose in any case.
Summary:
Most likely problems like this are caused by large companies "losing the ball". You wind up dealing with lots of minions, none of whom can see the overall situation. If you've tried all the reasonable routes to get satisfaction, then the law will probably do the job. In my case it allowed me to get the attention of someone with a brain.
You have to be 100% reasonable, and you're unlikely to recover anything more than your direct costs. You can't recover legal costs or "pain and suffering" costs generally. You won't make any money, but you might get satisfaction.
You'll need written records of everything. If they don't give you a receipt, ask for one. Write it yourself and get them to sign it if necessary (I did that). You need to avoid being anal though - you have to be "reasonable".
Don't go to law unless you're 100% going to win; don't threaten legal action, do it. "Barratry" is silly and I think transparent - people with a real case don't fart around.
Note that I'm talking about small claims here - stuff less than 5 grand.
Links:
http://www.nacab.org.uk/cabdir.ihtml
http://www.compactlaw.co.uk/preced1n.html
http://www.compactlaw.co.uk/smc.html
http://www.ofthelp.com/flashpages/itgrgcpgbtm_02.html
http://www.nacab.org.uk/cabdir.ihtml
http://www.lawontheweb.co.uk/
That is also what I thought - like after one month it goes to Canon?
Nothing I've read has any hard and fast time limits like that. If your retailer tells you that, they're bluffing. It may still be reasonable, but I don't think it's the law.
Someone please confirm that during my caravan's 3 year warrantee it
can go back to the local seller for a replacement - Now that IS
good news.
Caravans... not my favorite machines I'm afraid. First, presumably they cost more than 5k so the above doesn't apply directly. A 3 year warranty will be a part of your contract. If it says that they'll replace it if it fails, then you're in. More likely they will fix it, and so long as they don't take more time than is reasonable for that, you have to live with it.
http://www.wigglesworld.btinternet.co.uk/snow/thumbnails/IMG_11585.jpg--Philhttp://www.wigglesworld.btinternet.co.uk/ 
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