In the spirit of sharing...

[Carn]

I didn't count the actual passes but basically sanded them until you could just barely see where the original scratch was (as can be seen in pic 2 of my original post). What was left of the scratch was polished out with the 2 passes of Menz. I would advise caution when attempting this as it is very easy to go through the clear coat, ideally a proper PTG is required but they a little pricey at the moment

Also worth noting is that whilst these scratches appear to be quite deep they didn't look to be right the way through the clear coat, if you can see the base coat then avoid sanding at all costs (all IMHO of course)