Acquired a rifle recently with an incorrect rear sight fitted. I want to know what the sight was off. The sight is a dovetail one similar to that fitted to an early Webley Mk3 but much smaller.
Dimensions are:
Height of block 11mm/0.43"
width of block 16.5mm/0.65"
bottom of dovetail 10.2mm/0.4" This may have been reduced from a larger dimension to enable it to fit the rifle it was in.
Like the Webley Mk3, the adjuster wheel has an anticlockwise thread, but smaller.
The adjuster wheel and spring are missing.

Any help identifying this sight will be much appreciated,

thanks

dogsbody