You nee to be satisfied they have a defense, and it is as dubious as it sounds. I have only just joined the UKARA scheme as my site membership gets me on there, but have 7 RIFS, always had a good enough defense to buy new or second hand!
Pictures, or receipts of game bookings will count as a defense too, hell being a regular on here can be argued as a defense too, as long as YOU feel confident they are buying it for a legitimate reason, plinking or skirmishing etc (and are over 18) then you should be satisfied and sell!
Pictures, or receipts of game bookings will count as a defense too, hell being a regular on here can be argued as a defense too, as long as YOU feel confident they are buying it for a legitimate reason, plinking or skirmishing etc (and are over 18) then you should be satisfied and sell!