As this likely type wandered up towards the stream, I had an idea that he/she might try on the leap of faith across Stock Ghyll so I quickly changed lenses to the 135mm and waited.
Sure enough, lift-off occurred shortly after and somehow I managed to press the button mid-flight. Oh, and the flight was successful, with a smooth landing on the other side.
As an aside, the Leica lens I used was originally bought by Eliott Erwitt back in 1960, used by him for a few years, then given to his former partner Okky Offerhaus, herself an accomplished photographer. I bought it from a shop in Vienna who’d received it from her and it was they who told me about its history. It’s pretty beaten up and well-used, but it definitely has MOJO!