You happened to visit some of the whitest towns and cities in the country. The asian muslims are mostly concentrated in London, the midlands and the old mill towns of Lancashire and Yorkshire. Ethnic minorities don’t have much of a presence in the smaller towns and villages, or in the West Country.
Above is a map from 2005 - when I left. And the anglican churches were already dying. Catholic churches were a little better but the bustling ones were the Coptic, the black Baptist churches.
England has absorbed ethnic minorities before, but the problem is when the base culture is non-existent as is the case in large parts of the country.