The only equestrian statue in a Christian church, that I know of, anyway.
When you next come to London a visit to the crypt of St Paul's is worth while. An amazing array of famous Englishmen are buried down there, The Duke of Wellington for one, but there is also, Nelson, Christopher Wren, Lawrence of Arabia, and famous generals, admirals and statesmen going back hundreds of years. Pop in and say hello. They would appreciate the company.
I'll have to go up to St Pauls and take my own picture. This is the best I could find on the internet.
Here's a link to St Paul's Cathedral.