Dave,

I’ve checked a large number of B&W photos of the Supermarine and Gloster racers, plus contemporaneous artwork to try and ascertain the paint colours. The S5 was lighter than the later S6s and it also looks as if they may have used a non standard blue for the insignia, it is distinctly ligher than on the GIV in the same photograph. The S6s were, as you say, just about the same colour as the contemporary insignia blue and I would judge the current paintwork on N248 at Solent Sky to be pretty accurate.

Here is a photo of the float on S1595 showing the original bright blue paint below the darker top coating

Cheers

Ralph