The M25 was completed here in October 1985, when the long section from Reigate to the A3 opened. The helicopter service thus ceased 3-4 months afterwards.
In the shot of the Islander (above) the reservation phone numbers at both ends have been painted on the TOP of the wings. I just wonder who ever they thought would see them (apart from the photographer here). I've seen info written on the belly of the aircraft, to be read from below, but never on top of it. Maybe they hoped to get the bottom level in the Ockham hold ?