An attempt at a Visual Key (mainly) in monochrome will strike many as odd.
However, I have lost count of the number of times I’ve heard or seen:
… the colours don’t look like those in the book
The fact is that in nature there are natural colour variations, some quite subtle and some less so. Colours change throughout adult life, appearing washed out or completely different when immature, then often darkening with age.
Monochrome forces you to concentrate on markings and features which do not change, rather than on colour which varies. [I may slip into colour only as a last resort. :)]
To try to identify your specimen, you’ll be asked to make a few choices.