Saw the loops in Australia in the mid 1980's at the Adelaide F1 Grand Prix during a demonstration put on by the visiting RN
I didn't think it was possible until I saw it. Very impressive
If it was an RN Lynx and he was looping the aircraft then I’m glad I didn’t get in the airframe afterwards. ! Verboten. May have been an Alcock ( query spelling ) roll ? Which we also used to do in the Gazelle. Could look close to a loop from the ground.