Southcoasting Navigators no longer offer a compass repair service, but can supply and fit new magnetic compasses, if required.
Compass fluid.
A broad generalisation would put compass fluid into two camps:
Firstly, grain alcohol – such as gin.
Secondly, oil based – such as white spirit.
However, if these two are mixed the dome will become cloudy and impossible to read. So, a test must be made by extracting a small amount and mixing before topping up.
My recommendation is always to have a compass fully overhauled as the loss of fluid is rarely the sole problem.
I would suggest that B Cooke of Hull or Phoenix Navigation of Aberdeen are good instrument repairers. Both can be found by a Google search.