Chaps,
A minor up date, I have just had a 50 mile run to the coast ( thick sea fog but then it is Bank Holiday ) and the exhaust tail pipe is cleaner, still not shiny bright but better si I guess that's all the boxes ticked.
You'll have to be polishing the inside of the pipe now Reg. I took the 'oval' tailpipe thing off as it looked a bit too much Modeo to me for a classic, replaced it with a stainless straight pipe..around the same time as my ecu flash so hard to tell the difference on blackness but I don't get that dribble black stuff out anymore.