Jon:
There are only two lines of paints that I know of that carry the colors that you need. they are pollyscale, and Testors Acryl Model Master. Unfortinally model Testors discounted their marine colors, but you might have some luck ob ordering them on line.
Poly Scale has the Haze Gray and Beck blue, but you night want to use their Rail Road colors and used their Oxide Red which is a very close match.
I am sorry If I could not give you a spot on match to the lines that you have availablr to you in the U.K.. but you just might try posting this on eithet Steel Navy or Modelwarships web site. Youn just might find the answers that you need
DicK Wood