The trouble with quoting population statistics in terms of demanding an appropriate representation is that isn't there about 3% black population in England and Wales and 86% white?
If you're going to suggest going off population percentage when it suits the argument, and not the ability of individuals, then there'd be a lot less BAME players being selected than there are presently, not more.
I find it incredibly hard to believe that no teams, all the way down the pyramid, would give trials to the Asian players who, if they're as good as some claim, would then impress and work their way up the leagues as many players do. Or at least make waves at those levels for people to have heard of them and cite them as talented examples.
The idea that there's plenty of talented British Asians not even being given trials at any level, not just the top level, seems highly doubtful. If there's very talented players out there, looking for clubs, then some clubs at some level of the pyramid would give them a trial at some point. Or some would get trials in Scotland, Wales, Ireland, or other countries, and prove the English scouts wrong. The fact that just happening at all really does suggest there's a lot more to the lack of Asian players with Indian / Pakistan heritage than just these 'talented players denied by racism' claims.