I sympathise with the need for a system of defense such as UKARA, but to be fair to the OP, my son's situation would mean that if he were 18, it would be incredibly difficult for him to maintain a UKARA defense, and once I leave the UK, it will be the same for me. We'll only be back for a month or two at a time with lots of family visiting responsibilities to fit into a limited budget when it comes to car hire, fees, ammo, and possibly having to rent an air BnB for the duration.
Hence, as discussed in other threads, I maintain an album of site generated pictures of me and him participating in the hobby to help us form a defence of our own should we ever be pulled over by the fuzz with a car full of RIFs. Which I know doesn't help with retailers... but then this is the reason for this thread I suppose.
Mind you the OP didn't do himself any favours by not at least trying to explain the situation.
Just playing devil's advocate.