Paul,
That does not look like an original switch to me. It looks much more complicated with so many terminals, and that may be why some have been bridged.
My experience is that there are usually only 3 terminals, marked + (power source), D (right indicator) and G (left indicator. If there is a warning light there may be an additional earth contact.
If nobody else comes up with a definitive answer and there are no obvious clues to the functions of the terminals, I suggest you experiment with a meter across various combinations to determine which does what. Bon courage.
B….