It may not help, but so we don't get too muddled here, there are two unknowns I am interested in. Firstly, a Rebecca Tarling was born a Rebecca Wilkinson, in Riseley, married to a George Tarling in Middlesex, and in Southwark on the census after 1851. I know she was related to Sarah, the relationship could be sister, or sister in law. Ihave not found George Tarling's death or burial record, which might give a clue to where she was buried. She was definitely not a Rebecca Lowe by birth. Secondly, a Rebecca Wilkinson owned the burial plot the Ann nee Wilkinson and Reuben Brown family used. It seems plausible this was Rebecca nee Lowe (married to Wilkinson) as she was in correspondence with the cemetery well after Ann died in 1910 and they all lived in Walthamstow.