Did a vehicle /helo formation in the 60s in Anglesey. Valley had a weekly 'cash convoy' pickup from Holyhead, guarded by a 'Snowdrop' patrol vehicle. None available one Friday so we (the S&R standby) were tasked to stand in. Not sure what we were supposed to do, other than observe, but duly arrived, in the hover, at the bank, at the appointed time. Watched over the transfer of lolly and kept station as the van headed for Valley. Anglesey at that time boasted only one set of traffic lights - leaving Holyhead - they were at red! We duly came to a hover, recording a possibly unique occasion - helicopter stopped by red light! Proceeded on the green and D.C.O.