Ho ho ... I had to laugh on reading the previous two posts ... so much for standardisation. I can see it is a minefield and I had not even considered the dovetail angle.
For the record, I have a Parker Hale PH1 foresight that fits very well on the LGR and I assume the angle is OK. But I have a foresight which I think is a HW one, or maybe Original that although it looks as if it should slide on the dovetails, will not. The difference is minimal, but enough. I have not resorted to Swiss files ...
The rear dovetail seems to be standard 11mm, or as near as I can judge as a set of normal scope mounts fit OK.
I am still learning and really appreciate all the information being given.

Onwards ..
Cheers, Phil