St Anne and St Agnes is a church located at Gresham Street in the City of London, near the Barbican. While St Anne’s is an Anglican foundation, from 1966 to 2013 it was let to a congregation of the Lutheran Church in Great Britain. Wikipedia
Can prove to be a difficult church to visit. I have been twice and only got in to have a nose around thanks to a break in the music recital. The Friends of the City Churches recommend that you check with the church first:
Telephone: 020 7796 0149
Nearest stations: St Pauls and Barbican.