The Unfair Trading regulations cover other key issues too: it's an offence for businesses to pose as ordinary individuals, a tactic some chancers use to try and evade their responsibilities under the distance selling and sale of goods legislation, and it's an offence to mislead consumers by withholding key information or making false claims, such as time-limited special offers that aren't special or limited.
There's a big difference between what the law says and what companies actually do. If a firm isn't doing what it's supposed to be doing, we'd recommend collating as much evidence as you can and then notifying the company in writing - print or email - as soon as possible.
Don't write when you're angry, but do explain clearly what the problem is, what you want the company to do about it and when you expect to hear back from them. The Consumers' Association has stacks of helpful letter templates to help.
If a letter doesn't do the trick, it's worth putting in a call to your local Trading Standards office, whose involvement often persuades badly behaved firms to sort themselves out, or to file a claim with the small claims court. Such claims aren't as complicated as you might think, and you can claim not only for loss but for your expenses, including reasonable travelling expenses, loss of earnings and the cost of filing your claim in the first place.
Once again, the Consumers' Association has all the relevant information for England and Wales; the Scottish and Northern Irish systems are slightly different, and they're explained in depth on the Scottish Courts and the Northern Ireland Courts and Tribunals Service sites respectively.
Using the courts is a worst case scenario, of course: for most people, buying technology is a painless process, and most retailers and manufacturers are eminently reasonable when problems do happen to occur. However, it's nice to know that if things do go wrong, there's plenty of legislation to back you up!