Horseman Standard Repair

I have a Horseman LX 5x4. One standard does not lock fully - there is a couple of degrees of slop in the base tilt even with the locking lever tight. It usually moves when I insert the film holder Grrr! It isn't obvious to me how to take it apart to fix it, and Horseman repair centres in Europe seem to be rather scarce.

Does anyone have experience with fixing these, or can recommend a repair centre (Norway or UK preferred, but anywhere else would do ...) ?

Maybe Robert White in the UK can point you to some repair source. Or maybe Phootos in the Netherlands could help you out. Both of these sell Horseman cameras.