I have the full explanation posted waaaaaaaay back (about half to a year or so I think), but Italian ships mostly had wood colored decks (not neccesary made of wood mnd you) due to being covered in linolium. It still is used on almost every fisher boat you`ll find in napoli and southwards.
This had to do with their chosen `theatre`, the mediterrean, where the sun would `warm` the dark colored metal to much for comfort. RN and so who `came` there initially didn`t have this as they where pulled from other parts when the war started, byt the RM has been there and was build for use there.
It`s basically the same reason as why you where light coloured shirts on sunny days, and in those pre-Kyoto days, the med (italian side) had about 250 sunny days / year...