In the 16th century the Church of England broke away from the Roman Catholic Church, and all existing Catholic places of worship in England were appropriated by the Church of England or destroyed. Catholic churches remained illegal until 1829.
Is there a list anywhere of currently Catholic churches in London (or in all of England, for that matter) dating to before the English Reformation? The only one I’m aware of in London is St. Etheldreda’s Church, which was built in the 13th century, taken over by the Church of England in the 16th century, and (after changing hands a few more times) finally sold to the Rosminians, a Catholic order, in 1873.
Minor nitpick: The Catholic Church has been at pains to stress the significance of Bluff King Hal’s edict and its consequences (seizure of the monestaries, etc.), but in point of fact, there was no expropriation at the parish level. Parishes and their vicars went on holding services in the same way as before. You might look at it as a sort of corporate takeover, where “Church of England Pty.” shifts from being a subsidiary of Vatican Intl., S.A., and becomes a subsidiary of House of Tudor Ltd. ‘Company policy’ and ‘local outlets’ remained for all practical purposes same as before.
On what you ask – London churches which predate the Reformation that have changed ownership to the modern English Catholic hierarchy, I’m afraid I can be no help. But I did want to stress that the concept of the Beefeaters throwing Kindly old Father O’Malley out and putting an Anglican vicar in his place is far from the truth – if you as a churchgoer at that time happened to daydream through the formal reading of the Royal Pronouncement, you would not have noticed any difference.
Unless Kindly old Father O’Malley didn’t go along with the Act of Supremacy. Then he was out on his ear, and probably also short a head. And, in 1547, parish chantries were dissolved and outlawed, and their funds expropriated, and a lot of parish priests did find themselves out on their ear.
Don’t downplay the effect that the English Reformation or the break with Rome had. If you as a churchgoer at that time happened to daydream through the formal reading of the Royal Pronouncement, you most definitely would have noticed a difference; i.e. the abolition of the chantries and parish guilds, the introduction of the Book of Common Prayer, the seizure of church goods (altar cloths, communion chalices, etc), defacement of statues, destruction of altars, whitewashing of religious murals. All of this stuff happened in the reigns of Henry and Edward, and it all would have been noticeable.
I think St Etheldreda’s is the only one in London. St James’, Spanish Place, while providing a haven for Catholics for many years during the “difficult” times, was not built until 1791.
As for outside London - the Wikipedia article on St Etheldreda’s refers to Saints Leonard & Mary Church, Malton, North Yorkshire (in the Middlesbrough diocese) as dating from 1180, and given back to the Catholic church in 1971.
Much of the City was burnt in the fire of 1666 and further damage in WW2 ensured that very few genuinely pre-16th c. churches survive - many parishes have been amalgamated or snuffed out with the decline in the City’s population on recent centuries (mostly business district and few actually live there).
I don’t know about liturgical differences between Catholic and Anglican masses at the time, but I would expect the very substantial (pun intended) theological differences between the two when it comes to the interpretation of the Eucharist (transsubstantiation or not?) to be reflected in the importance accorded to it in services. That would certainly be something noticeable to churchgoers, and probably also be understood by them in its theological significance. In fact, the difference is so stark that during the centuries in which British governmental officials were not allowed to be Catholic, it was used as a way to differentiate between Catholics and Protestants by requiring officials to take an oath to the effect that the bread in the service is declared not to be the body of Christ.
A more practically visible effect of the English reformation would have been the dissolution of the monasteries, which actually were appropriated, together with institutions annexed to them such as Cardinal College, Oxford - now Christ Church after its re-institution by Henry VIII.