It looks like it was RAF and Army.
In Robbie Shaw's book on Kai Tak, The Final Decade, there are a number of images of helos with RAF numbering and in one case a Royal Air Force Wessex.
He says they were operated by 660 Squadron. On the opposite page to the Wessex is an Army Scout .Later there is an image of an S76 in VR Rego when they became the GFS.
Wunwing