Good question. I am none too sure of the answer so will be interested to hear if anyone has any views.
I have looked through the Instruction Book for the 105hp Daimler engine and transmission set and can't find an obvious answer. However, it does make reference to a small brake drum fitted to the rear end of the worm shaft. I think that's the component between the two parts you refer to. The Book says that this brake drum is operated by "the side lever provided through means of bevel gear and toggle". Could what you have highlighted be this?
Thank you very much for the reply. I assumed that these instruments somehow work with the brake drum. As seen in the photo 07 brake drum closely adjacent to the reduction gear.
But the drawing is 08 between the drum and the reducer is installed 09, perhaps this is control the brake drum.
Maybe someone has pictures from the brake drum, and if possible from the clutch. I would be very grateful.