I was wondering if someone might be able to give me some hints on this one. The watch is a Medana, made by Meyer & Studeli, probably in the late 1920's (there appears to be a service mark dated 1927). I think the top stamp on the back might well be for the manufacturer, which would make these Swiss hallmarks, but.... The watch by the way was bought in the UK, but doesn't appear to carry import marks which it should have if these were UK hallmarks.
Inside the case back
There is also this on the side of the watch