Handy that I should have recently obtained Mal Wright's British and Commonwealth Warships of WWII. It illustrates three schemes used on the Isles Class.
HMS Arran, 1943 in dark grey hull with light grey upperworks and black/dark grey foremast and medium grey aft mast.
HMS Islay, 1943, in a Western Approaches light pattern – white hull with light pale blue and light pale green swatches, and white upper works, light pale green tripod masts.
HMS Calvay, 1944, in a light pale green hull and upperworks with medium green swatches on hull, light grey verticals on after deck, medium green funnel and light pale green masts. Calvay did mostly inshore work so the greens were intended to blend with the shore rather than the sea and mist.
Decks for all three show a working, or mine, deck in natural wood, medium grey upper decks and dark grey focsle. Decking on the gun platforms forward of the bridge is shown light grey.
Hope that gives you some ideas. Google pics of ships in the class (best to do so by ship name) to see if you can get an idea of specific patterns for the colors on the ships.