I fly 8 seats under 45 tons/NCC IIRC there the rules changed with NCC or just coinciding with introduction of NCC. Operating JAR-OPS before up to 8 Seats and 17tons we had an aircraft search in the OM-A, but only had to do it on unprotected airfields. (no fence -> search the bloody thing) IŽd guess North Ireland <-> UK in the seventies is a different story from this...