I have followed this thread with great interest, as I am sure many others have as well - thank you to all who have made it such a fascinating read.
My (very) tenuous connection to Ken Davies was that my PPL(H) was conducted by one of his old friends at Barton. During XC Navex trips across the Cheshire countryside and onto Hawarden, I'd hear intriguing stories about their past exploits involving a variety of aircraft!
I'm afraid I cannot add any further to the G-TALY story but I do have something else to offer...
Having grown up in Glasgow, I was interested to see photographs from Scotland that demonstrated B206s in a variety of guises. My brother and father were gifted a helicopter trip in the late 1980s from the Clyde Heliport - I am not sure who the operator was, but my father tells me during the trip, the pilot had to do an "Eye in the Sky" report for Radio Clyde, further suggesting it was one of the B206s. I asked him to send me any pictures he had and the result should be shown below...
Clearly this is not a B206! Tracking the reg through G-INFO, it appears that this was an Alton Towers aircraft at the time (1987-1990). Why it was in Glasgow doing traffic reports and pleasure flights, I cannot say, but thought it might provide another interesting thread drift of nostalgia.