I can answer my own query after all that, but it might help others. My Mary WAS Mary Tidd of Clapham. I had discounted this until I discovered there is a Huguenot cemetery (Mount Nod) in Clapham Wandsworth. (I am in Australia so not very familiar)Mary's son married a Huguenot weaver too so it became apparent. Also why they may have married in a non conformist chapel, but could be other reasons. The clergyman must have asked for her name and parish, and she said "Mary Tidd, Clapahm" And it was her husband Richard Hart who was from Marylebone!!!