Every Church of England parish comes under the care of a priest (Vicar, Rector, or Priest-in-Charge). Everyone living in a parish (whatever their belief) has certain rights within their parish church. These include the rights (subject to certain conditions) to baptism, to marriage, and to a funeral service. Banns of Marriage have to be read in the church in the parish where you reside. In the case of a Christian funeral at a crematorium, your own parish priest is normally approached unless you specify otherwise.
The original parish boundaries for St Mary’s were set in 1855, the parish achieved its present arrangement when St Mary unified with St John The Divine in 1985.
The map of the parish boundary on this page is courtesy of acny.org.uk.