RtL,
I still use the Humbrol enamel range which must make me a real throwback
My British 28mm troops are painted with three layers: a base coat of 73 which is a kind of Guards maroon (really the colour that sashes should be); a 50/50 mix of 73 and 60 (which is the 'British red' you referred to) followed by a highlighting coat on seams, elbows etc. I used to use unmixed 60 as the highlight, but I now put some orange in it. I have come to the conclusion, looking at paintings at the NAM, that something orangey is most appropriate.
It is certainly the case that painting bright colours like red, yellow or white with enamels is hard work. My gunners and blue coated folk, I have hitherto done with only two layers.
regards
EC