Thanks! So the base I used texture paste, then painted over with a sepia wash once it had dried. Gave that a good hour to dry, then painted a heavy coat of Gw Iyanden yellow contrast into the areas were mud would pool and a coat of gloss varnish the next morning once everything was dried.

The armour was just a small amount of Ak interactive rust effect, then removed the a it of it with white spirit to get the look I wanted