The wedding entry is a copy from the Thames Ditton Parish Registry of the marriage of Nathaniel Lucas and  Margaret Mitchell both of the parish. They were married by banns on 25 Day of August 1782. Nathaniel signed his name and Margaret made her mark. The signature is from Nathaniel's letter to his father written on Norfolk Island 1796.
It is thought that Margaret Mitchell died on 24 March 1784 - Mrs Lucas -poor.  (Thames Ditton parish registry)
There was only one Lucas family in Thames Ditton at the time and Nathaniel's mother was still alive in 1799.

Nathaniel Lucas's Signature