Rear wiper od my defender was not working . took it apart & found wire to one of the brushes was broken . are spare brush's available off the shelf?

I couldnt find any myself when i repaired my rear wiper motor.
What i did was got a set of brushes that i got spare with a grinder and rubbed them on wet ' n ' dry paper until they were the correct size to fit the brush holder, Cleaned and greased up the gear wheels and reassembled, 18 months later still going strong, Right enough mine was siezed and the two brushes were worn right down, you can buy brushes off of ebay but there not the right size