You’ve just bought a new kettle for the office, but you missed the PAT tester, does the kettle need testing now? Will you have to call the tester back out and pay a call out fee? 

If you can be sure the new items have been purchased from a reputable supplier, are genuine manufactured and not counterfeit, British Standard with UK plugs on then there is probably no reason to get the item PAT tested before use. If you are at all unsure, then you should.