FERM FKZ-250 Mitre Saw brushes ?

I need new brushes; the old ones seem to be unlike anything advertised for this model, they are 6x14.7mm in contact with commutator, but at a guess, at least 15mm deep (so more than that when new); also, they have a stopped groove down each narrow side to stop brushes coming out of brush-holder. Also, the wire terminates in a simple rectangular flat piece of brass. Bought in 2002. Anyone any advice?