John, do you mean G-AXAY with John Perry, on the Plessey contract?
No: there was a 206 that (IIRC) lifted from Battersea only to have the jesus nut come loose. Rotor assembly went up, fuselage went down, fortunately from a low altitude as all on board just got a bit damp
Back in the '70s with no internet or mobile phones, so by the time the story travelled it may have been well embellished
Memory is hazy, someone is bound to remember the actual details/story?