Hi Gary
Just a few more bits and pieces which may connect someday

I had a look for baptisms after 1795 for children of a John and Sarah - I couldn't see any only children of a Thomas and Sarah, whether this is the same couple and John was known as Thomas I really don't know.
John son of Thomas and Sarah Upton baptised 18th Nov 1798 could be your John. No sign of Henry.
Found these burials which could be relevant
Sarah Upton of Southwick age 54 buried 9th Jan 1829
John Upton of Southwick age 83 buried Sep 1852
Also checked baptism of Virtue Martin's brother
Richard son of John Martin
Smuggler and Virtue his wife was baptised 26th Oct 1800
Interesting occupation!
Jan
