Hello Steve, thanks for the explanation in colour choices.
FS 36118 is actually quite close for Extra Dark Sea Grey, so it was the green that led to my enquiry. Nick Millman's colour studies, has FS 34096 as being a bit too green for Dark Slate Grey. Think more greyer, and since Grumman was using Dupont paints matched to British requirements, it would be a bit different in that aspect as well.
regards,
Jack