Hi Andrew,
I would ignore RAL colour codes as they are European origin. The British Standard colours are still used by paint suppliers in the UK. I am not certain on the shades of blue and red on the RAF roundel, but at a guess would say Royal Blue and Signal Red, both are BS shades.
Just found that on the BS381C colour chart there is 110 Roundel Blue and 454 Pale Roundel Red.
regards, Richard