I have searched ancestry.com about 250 family public trees, and did not find mark and sarah.
I did find a marriage, my source is: All London, England Marriages and Banns 1754 - 1921. Mark Gardner Marriage 29 May 1883 St James The Great, Bethnal Green. Tower Hamlets. Father: Edward William Gardner. Spouse Father: Edward Street. Household: Sarah Ann Street. Don't know if this helps, still searching.