Well, in preparation for TRC's regalement (at some point in the near future) of the Twyford Moors 'ditching' on 17th August 1973 at Battersea .. let's re-set the scene with a copy of the snap from the Wessex Thread:
A 'White Top' Wessex (aka Green Parrot or Admiral's Barge), used for liaison duties by senior Royal Navy types and most probably a Mk V, departs Battersea Heliport in London on 17th August 1973 and overflys a 'parked' Hughes 300 (G-AXXD) belonging to Twyford Moors Helicopters