OK, having stripped the primer and wash off the 2 figures, cleaned up the mold lines I'd missed, re-primed and re-washed them I had a sudden thought.
"Hmmm. I'm going to be trying a) a new technique; b) painting a camo pattern I haven't done before. I really ought to do a test figure to check if the technique works (and find out how much I need to thin the paint down) not to mention checking if the colours I was planning to use are right."
I didn't want to use one of Dux's figures for this, but a quick hunt confirmed my suspicions - I did have a pack of Airfix 1:32 scale WW2 British Paras. So, I grabbed one of the figures from the pack, gave it a good scrub with warm soapy water, rinsed and dried it and set to work priming and washing it. I discovered that the plastic did not like having primer applied, but persevered and got it coated in the end. Once the primer had dried I did the pre-shading wash, then left it overnight.
This afternoon I started work on the test painting. Here's the result (one of Dux's figures alongside to show size):
The metalwork on the Bren doesn't look quite so shiny and the pre-shading does show through somewhat - there are subtle differences in the shading of the colours.
I discovered the following:
I didn't need to thin the paints quite as much as I thought (I think the drops from my wash-mix bottle are larger than the ones from the Vallejo paint bottles)
The base colour I'd used for the flesh (Saddle Brown) was a bit too dark, although probably about right for the lips. It might be OK for a final shading wash.
The base colour I'd used (mix of Pastel Green and Brown Violet) for the Denison smock was too light - I'll use a mix of Green Grey and Brown Violet instead.
The red-brown I'd used (Red Leather) for the Denison brush strokes was too light - I'll use Mahogany Brown instead. The Red Leather will, however, make a good base colour for the flesh.
I'm happy with the rest of the colours.
I'll make a start on Dux's figures this evening.