I wonder if anyone can offer a picture of the variable selectivity
arrangement of
the Eddystone EA12, which I believe was also used by some other
manufacturers?

This was the scheme whereby coupling between the primary and secondary of
IF
transformers was varied nechanically by distancing the two halves of the
transformer
from each other.

I have access to photos showing the operating levers, but what interests me
for
the moment is to have a peek, or peeks, inside the IF cans themselves.