Leotax needs rangefinder repair, Who in UK?

[mechanical_vandal]

If this is exactly like a Barnack Leica (which it appears to be) the screw you turned (yellow) is just to tighten or loosen the grip on the horizontal adjustment screw (centre of red). Basically the adjustment screw (red) is threaded into a block in two pieces, which are held together by the yellow screw. The tighter the yellow screw, the more difficult it is to turn the red one.

To adjust vertical rangefinder you turn the "window" on the left with the two notches. This is not exactly plane so turning it will change the image position.

Ok cool. On this one the vertical was pretty good to start with, I thought adjusting the yellow screw had knocked it out so I undid whatever I did but maybe it was just late night brain fog!

The other one definitely needs a vertical adjustment so at least i now know how to do that correctly!