It seems that ballasting this track is going to be a life long pursuit ! But it is strangely therapeutic.
Contrary to my previous thoughts I didn't watch Avatar again, mixed into an evening of ironing and being Dads Taxi service, I sneaked to the shed for about 40 mins and ballasted another foot or so of track.
It was the bit over the plate girder bridge and directly under it, The bridge had a coat of grey acrylic too.
Today work takes me to the village of Dobcross to modify and assemble a 6x4' flatpack garden shed for a customer to keep his garden furniture in, and tomorrow I will be spending the day sat on a church roof replacing stolen lead, its a varied life !