An excellent reference source with details on a lot of aspects of finish repairs is Charles Harding's book Furniture Doctoring and French Polishing. Its written in a very easy format, and should cover most surface defects, and how to deal with them, that the ordinary wheeler dealer will come across on their car booters outing for cheap antiques. If you come across the early old 78's as well, broken and for nothing, take them. As they are shellac , and were used for resurfacing old ebonised pianoes ect. So they will be part and parcel of the restorers kit..

Some damn good tips in here

It's going to take a while to build up skills. You could look for a local course psketti. I know you're in Scotland, but don't know if you're near a city or in a city. Mind you, I'm not and there's one round here.