I have a book dating from 1969, 'Fighting Colours' by Michael J F Bowyer, which states that on July 24th 1941, Hawkers produced drawings to change the top colour from brown to 'ocean grey' though this later became known as dark sea grey, the real Ocean grey, with it's hint of blue, came later. At the same time the underside was to change from duck egg green to medium sea grey.
Now that is No 165 in the Humbrol range & looks a bit dark to me. Though I'm no expert
& I hate to argue with Mr Bowyer, who is.
It's probably going to come down to how the individual aircraft that you want to model was painted, if you can find out for sure.
No 165 is a satin finish, if you want matt I'd go for No 64, or, for a worn look you might get away with No 28 if you dirty it up some.
good luck & Merry Christmas.
Pete