After applying the decals and sealing them in with another coat of Tamiya X-22 gloss varnish, I applied a panel line wash to the model using Mig Productions Dark Brown wash on the top side and PLW Blue Grey on the undersides.
Both colours were brushed on, left to dry for an hour or so then wiped off with kitchen paper towel leaving the wash in the panel lines. For the lower cowlings I used the dark brown wash as pictures of this particular aircraft show it to be particularly stained.
The model will then be sprayed with Winsor and Newton acrylic matt varnish and when dry I can start finishing the model (and stick the bits I have broke off back on, just don’t tell anybody I did that).
I didn’t use the dark brown wash all over as I felt it would have been too dark on the RLM76 undersurface colour. I think the blue/grey panel line wash worked better instead.