Mucker,
Apart from this Mauve P40m, I've built the Academy B version, as the mount of Clive Caldwell with 112 RAF Sqn in Nth Africa, several of the AMT E and K versions, a couple of the Arri E's as well as the Airfix boxing of the inaccurate Dick Creswell replication [A29-113 is a blue 'U' and not a red one as most decal sheets have it as]. Along with the Mauve P40n as the mount of Geoff Atherton, the Eduard P40n Profi Pack version [which is in the stash], will one day get built.
Daniel,
The blue on my P40m is Humbrol # 14 applied over a white base, as for the spinner cap, this is what I did to mine:- [The spinner cone is not fixed to the model]. Using blue tac and a piece of sprue [to hold the cone while airbrushing], I painted the spinner cap in white primmer, when dried I used 6mm Tamiya tape using the fine line on the spinner as a guide, I wound the tape around the cone from the prop end and pressed flat.
Using the airbrush to paint this part, I painted fron the prop end to the tip as this gave me a much better line without the paint bleeding under the tape.
Another thing you might like to try is Frisket Paper, this is a clear self adhesive film that printers use and can be found in most art suppliers.
I hope this helps a little.