Hi Gents. I was aware of the information which 'salopian' and 'Imperdix' have referred to. Unfortunately, it does not help.
Unless an expert can read between the lines by looking at my photos, the quest may be a dead end. The many members whom provided detail of the trigger system have my eternal thanks.
I can take better photos but I cannot yet come up with a website onto which I can download them.
Any clues men???