If he wants to buy a gun - or even transport someone else's gun to a shoot - then he has to have a licence.
Years ago I used to clay pigeon shoot, borrowing my then boyfriend's guns. If he didn't fancy going along to the club (which didn't have facilities to store guns), then I couldn't go as it wouldn't have been legal for me to have the guns in my car.
I then decided to get a gun - but had to make it clear to the Police Authoirity that I would never be storing the guns in my own house, so I didn't have to get a cabinet. I just wanted to be able to travel with them legally.
Like PPH syas, the UK laws are so strict that the risk of an accident involving kids (or others) is incredibly low.
Freckle - clay pigeon shooting IS done with a shotgun - the fact that there is a "spread" from the pellets is part of the skill involved.