I saw a fragmented procession going through Caerphilly and to be honest it just loked like the back patch brigade were on a rideout, a load of old scrapyard dodging bikes and trikes

On another not about the back patch wearers, i saw a procession going through Risca today and half of the riders werent wearing helmets, i know you dont have to wear them on trikes, lets face it they're not bikes so why should you have to but these were two wheel bikes.
Do they have special permits with regards to non wearing of helmets?