Well I got the will of John Ashendon from the National Archives, it says he is from (or at least living in) Essex and it does refer to his daughter Mary Maria wife of Richard Marchant, unless there was more than one Mary Maria Marchant around at the time, this is fairly good proof and the link I was looking.
for. before accepting Mary Ashenden as his spouse
Also included with the papers sent, was the will of Hannah Marchant, widow of Richard Robert ? (I can't read the surname).