This evening things came to a head when all kinds of electrical issues started happening on the car and by the time I got home it wouldn't even turn over.
Double bugger because I need the car for the next couple of days so I needed to see if I could bodge it up... I sprayed some contact cleaner in and gave it a good twatting to no avail
With nothing to lose I stripped off the brushes to find one was fine but the other mullered. Then I remembered I had an E30 alternator in the garden. The dirty6 takes a Valeno alternator and the E30 is a Bosch unit so there was no chance of a direct swap...
Instead I stripped just the individual brush from the Bosch unit and "retrofitted" it to the dirty6 unit
It was larger so required some shaving down with a craft knife and I could seem to desolder either one so I just shaved off the excess on the dirty6 brush. Sliding the new brush on top of the old one and checking the resitance turned out all good so I bolted it up and hey-presto... 14.2 volts from idle. After leaving the battery for a while it started the car and after a drive around she was back on form - with enough brush left for a good few k more
Orignal brushes from the dirty6:
Original e30 brush removed:
E30 brush stripped out ready for "modifying":
The final assembly in to the dirty6 brush unit:
All in all a nice evening's bodging
Can imagine it sitting there in amoungst the grass 
