I forget how beautiful the front of St Paul's is. Did you go inside at all? One of my friend is an official guide - she works four days a week and does this on the fifth day as she enjoys it so much.
@paulaw Yes, I did go inside Paula. I had a free morning, so headed there and went right up to the top - it was a clear day, so great views over London. Then I walked over the Millennium Bridge and round to Borough Market. London is a great city - very different from Paris, but just as wonderful.