Okay, questions, questions, questions.

Why has the USA standard grown up so differently to the UK standard. How did both these standards come about? Are their any other standards for Nankins worldwide? Is it a good thing or a bad thing that they differ?
UK calls for white or horn beak – USA Horn, shading to darker on upper mandible
UK eyes bright orange – USA Reddish Bay
Both match on comb, face, wattles and ear-lobes. Legs are similar only marginal variation is the UK says blue or bluish-white where USA just says bluish slate.
But the colour descriptions are very different. If you put together what you’ve described. Then for both females and males your looking for under colour of light, golden chestnut with plumage that is deep black cherry red with black tails. The red being glossy.
I’ve already posted the UK male colour standard for the female from the same source it says
Female plumage: Neck, back, wings, tail and saddle dark ginger-buff. Tail shading into black at the ends. Remainder of plumage light ginger-buff throughout to the skin.
I had a look at the colour standard for OEGB black/red and it has 2 forms described Partridge Bred and Wheaten Bred so which one would the USA standard be referring to? Or is it meaning The Ginger-Red(which has a black tail)?
Makes me wander how similar or different the rest of the standard is?
Mousy.