What a lot of replies since my last post!

Deb, you are brilliant. I love your logic and how you went about hunting down Ann Gullan. Fabulous work!!!
Yes, Mary Shepard has still not been found on the 1841 census. When she married she was 'of Dean Street', and I think someone checked the whole of Dean Street in 1841 but couldn't find her. It's possible that she wasn't at Dean Street on census night, but where on earth was she? Horribly mistranscribed? Dittoed under someone else's surname? Did she call herself Mary Shepard or Mary Bryceson or Mary White? She was Mary Bryceson, widow when she married Matthew Ward.

avm - I'm glad you've joined us.

Interesting stuff about the Land Tax Records. There are so many things that most of us don't think of checking.
I'll have to dig it out, but at some stage I think I made a list of all the residents of Richmond Buildings (can't recall which census it was though) - there were loads of people living there, and many of them had 'foreign' names.
Back to Matthew Ward ... I wonder if he was buried with Mary? Graves? Headstones? As we are talking London here, unfortunately I don't think we have a chance of locating them.