Maybe there is a Brit on the threads who can enlighten us. I was there 3 years ago, attended Evensong there which was quite Anglican. The minister with whom we spoke shared the information that until the Pope denied Henry the 8th a divorce, Westminster Abbey in London was Catholic and after Henry " divorced" himself from the Catholic Church, the Abbey was then coverted to the Anglican religion.
I just did a google search on Westminster and there is a Catholic Diocese there and there may be a Catholic " cathedral" there that goes by that name. But the famous Wesminster Abbey is Anglican and the seat of the Church of England and Wales. Once upon a time it was a catholic cathedral as were all cathedrals in England until after Henry the 8th and Rome had the falling out over his wish to divorce Catherine of Aragon of Spain because she produced no sons....and Henry had spied Anne Bolyn (sp)who became the mother of Queen Elizabeth I.