Thanks guys for your compliments, here are some progress images of the paint process.
The base coat was a khaki brown I mixed to resemble the colour of 'Lodestar III' in Brussels. The hairspray technique was used to chip, except I used AK Interactives Worn Effects fluid instead of hairspray.
Satin varnish, then some more Worn Effects fluid. Then a layer of acrylic paint mixed to resemble dust or dried mud was airbrushed in a light coat, and partially removed with a wet paint brush as per the usual hairspray technique.
This was followed by streaking, pin washes and general shading with oil paints.
These were the basic steps I followed. Each project is tackled differently, but for the last few builds I've used the hairspray technique for chipping, light layers of acrylics for dust/dirt, and various other effects using oil paints (inspired by Mike Rinaldi's Oil Paint Rendering technique).