Hello Alex and welcome to the friendly BSA A7/A10 Forum. As a newcomer to the BSA scene an A10 would be a good bike for you. Basically they are available with either plunger frames or swinging arm frames, tourers and sportsters.
I won't advise as to which model to choose because members who run the plunger models will recommend them and the swinging arm owners will advise these. So without offending anyone I would simply suggest that the choice is yours but go for a tourer to start with.
As was suggested previously try to find one with original tinware that is up and running. An A10 as a box of bits can be a tempting buy if it is cheap enough but can easily run away with your money.
If you get one that has had the engine rebuilt, ask if the sludge trap has been cleaned out properly. This is the centre of the engine and will stop the flow of oil to the big-ends if it has not been cleaned out. In fact this job should be done every time the crankcases are opened and the flywheels removed.
There are many BSA owners in Denmark and it would be a good idea to be in touch with some of them. They would be an excellent source of information for local spare parts suppliers and engineering facilities.
Try contacting Steen Christensen, secretary of the Dansk BSA Klub. His email address is Secretaeren@bsa.dk
Finally, for now, if you do get an A10, get yourself a workshop manual and a spare parts list for your particular model. You will find these invaluable and an absolute necessity to keep the machine on the road.
Good luck.
Beezageezauk.
