Quoting ethnic demographics is pointless because it ignores the obvious point, that not all people crammed into that bureaucratic box are alike.Can you at least try to explain how it’s mental gymnastics? :/ Come on, you clearly have a strong viewpoint you care about. Try to do it justice.
However, television, and the media more generally, does force people into a box, in the name of "authenticity" (and quotas).
(The quotas being a new version of the production game from the Mary Whitehouse days of script editors haggling over whether "two bloodys can be traded for a bugger" but played with people)
As pointed to by linking to Amazon's casting requirements (all companies have them).
Ergo, (and this is something one hears often from "minority" (of all kinds) critics of "woke"), what is produced reflects not "authenticity": but a new stereotype.
And that stereotype is something both created by and reinforced by arguments such as Manchester has xx% whatever therefore y... particularly with the advent of "cultural sensitivity checkers" (or the "woke" version of Viewers and Listeners Association) - (the difference being that they are inside the building rather than sending letters in green ink from outside).
That said, I'm rather baffled as to why you quoted those figures for Manchester and Leeds.
Since the point is, and always has been, one of class not race.
As it is rather pointless decentralising to make television less Londoncentric, if the exact same type of person - regardless of sex, race, ethnicity, etc - is employed as would have been employed in London.