Hi Vladi,
The green flight deck is not unknown - it's in the Rate Books from 1933 on as pattern 631 Bronze Grey, a colour comprised of black, white and yellow ochre. It makes a dark dirty sea green sort of colour, and was the only paint prescribed by the Admiralty for carrier flight decks until the availability of non-slip paints in the full range of colours which was, from memory, mid-late 1941 I think (dick may correct me on the exact date):

On the subject of camouflage, Raven in his update is probably closer to the truth. It has been known for a while now that pattern 507A and pattern 507B were the same shade of Home Fleet Grey. 507B was introduced following a 1929 survey of ship captains to determine whether a higher quality enamel paint would reduce the workload in repainting their ships. The consensus was "yes" and 507B was introduced as Home Fleet Grey with enamel varnish tinted to Home Fleet shade added to make it harder wearing. Early on in the war the Admiralty ordered use of enamel to be suspended for war economies and reintroduced 507A as exactly the same formula but without the tinted enamel varnish in the recipe.
So, there were no camouflage patterns made up from 507A and 507B.
Large ships did tend to have one-off designs which little seems to have been formally recorded, but the Admiralty did have views on combinations of shades for 3 colour Light Admiralty Type camouflage schemes up to 1942, prior to the withdrawal of MS1,2,3,4,4A,B5 and B6 and their replacement with G5,G10,B15,G20,B30,G30,B45 (later G45) etc from 1943. If we ignore the designs (printed on colour plates showing suggested disruptive patterns) and consider the combinations of colours as ones definitely used together elsewhere in the navy we could also consider:
1) 507A, 507C, MS4A

2) 507C, MS2, MS4A

3) MS2, MS4, MS4A

4) B5, MS4, MS1

5) 507C, MS4A, B5

Of those (published in Confidential Admiralty Fleet Order (C.A.F.O.) 679/42 "SEA-GOING CAMOUFLAGE DESIGNS FOR DESTROYERS AND SMALL SHIPS" in 1942)) the photograph itself suggests that the darkest shade on HMS Hermes was probably either 507A Home Fleet Grey, MS2 or maybe B5 perhaps. B6 may be a candidate for one of the lighter shades, but contemporary practise for 3 colour schemes on smaller ships at least tended to favour MS4. The above is by no means intended to exclude any other suggestions - but 507A and B were the same colour - Dark Grey, Home Fleet shade.