it also said
"The brushes looked so similar to what you'd find in an alternator, serving the same purpose anyway, that I went to a shop ("Electro Maintenance" in Baldoyle) to find something suitable. A guy came out of the back room and took the disassembled holder away before coming back with some Delco alternator brushes, for which he charged a pretty reasonable €7. He also suggested that I snip off the old brushes, leaving just the bit of wire that was somehow attached to the metal mount, and then solder the copper wire of the new brush on top of that. Before doing this, we threaded the old black plastic insulation piece onto the wire, fed the spring through and cut off the excess wire (to stop the brush from falling out the end of the holder!). "
so possibly, bodge something together out of parts that sort of kind of maybe look a bit like the brush holder and hope for the best?