IF you have a Moss box, and IF it is the same/similar to the one in the Jaguar XK120 (which started in 1948) then this may be of use:

https://jaguarrules.ru/wp-content/uploads/2018/08/Jaguar-MK-VII-XK120-Service-Manual.pdf

see page 166 for an exploded diagram of the box.

Dave
Blue 4/4 1969, Green +4 1953, (different) Green +8 1977