This is a small St Mary's hidden beside a "big hoose" which is now called "Cowley Manor Experimental" (I think this means it's "experimenting" at being a very expensive 4* hotel.) It has a "Wellbeing & Spa". You can't see the church at all in this photo 'cos it's behind a big hedge - but it is there, honestly!
The church is quite small with a tricky door that takes a bit of pushing to open but magically locks itself at 6pm. It has a font and an organ with rather prettily painted pipes.