Many local authorities have set up lists of businesses that have passed a stringent vetting process, carried out by Trading Standards, so you can be sure that these are reputable. This means that they have no adverse history of consumer complaints and that they have agreed to follow the spirit, as well as the letter, of the law.
Things will still go wrong sometimes, but Trading Standards will be there to help you if you are unhappy, and they will remove any business from the list if they don't behave reputably. Referenceline has been proud to support a number of these schemes for over 10 years, starting with Dundee in 2005. Click on the logos and links below.