Enamel paints don't play nicely with HaT's new plastic, and the official word from HaT is use only acrylic paint. But Humbrol do make acrylics in many of the same colours as their enamel range, I'm sure that's what the guys are referring to.
I also use Humbrol 25, but Oxford blue should be O.K. as well, or any other standard dark blue from other makers.
According to Haythornethwaite the colour of the Red Lancer's uniform was scarlet. I use humbrol scarlet No.60 and it looks good; but, again, any equivalent paint from other makers should be fine. .