Elfyn,
PAT (Portable Appliance Testing) is something we all do have done on a regular basis - Right?
It is a requirement made by several pieces of legislation, including the Electricity at Work Regulations 1989. The scope of appliances covered is wide, not just your
vacuum cleaner, portable extractor etc. but basically any thing connected to a mains plug - including an extension cable and 110 volt equipment.
Implications of ignoring this requirement can be serious. Not the least being the fact that you could find yourself un-insured.
You are entitled to carry out these tests yourself - a one-day City and Guilds course is available (£160 + VAT) and the equipment can be purchased for around £600. You may consider that this investment is worthwhile for the convenience of being able to test at a time that suits you and the cost, like the cost of having the tests carried out by some other qualified person, is tax deductable.
There is also the possibility of earning additional income by testing for others. However, I would sugest that in the event of an electrical accident occuring, due to a fault that develops between tests, then certification by an independant party is likely to have more credibility.