I wouldn't hold out much hope of hitting much with a period BSA scope - they're better for display than use and open sights are a lot more useful I once had a Nikko 4x32 on a Mk2 but had to get a wider mount from John Knibbs for the 1960s scope grooves on the BSA.
Have you considered an aperture sight Jon? They tend to sharpen the focus of ageing eyes but do require a decent level of light to get the best from them. I sold a Parker Hale sight on here last week that would have been ideal.
Kind regards,
John
Currently looking for Baikal Makarov pistols with the following prefixes to the serial number: 98, T01, T09, T21, T22
Prefer boxed or cased but will consider loose examples too.