Hercus lathe tachometer sensor mount

Mount to fit a hall effect taco sensor to the rear gear cover which attaches to the bracket for the outer gear cover on a 9" Hercus lathe.
Mine is the craftsman version of the Hercus 9" which has a slightly different headstock from the standard herbs 9A, 9B 9C, although I believe that the gear cover and gear cover mounts are all the same. I am note sure if the standard 9A, 9B or 9C lathes share this inner cover or not.
This mount is a slip fit on the top corner of this cover as per the photos.