In the US just about any general practitioner ("regular doctor") can do this for you. I know my insurance covers it, no problem. They even do test levels
As far as Randy claiming he feels better and has more energy, that doesn't make sense. The test alone effects no change in your energy or anything else. It's correcting areas of deficiency based on the test that will help you but if you aren't eating like a moron, you shouldn't be especially deficient anywhere.
I don't know how it works in the UK, but go to your doctor and ask, it's not a big deal.