James,
Its not an easy family to trace is it? My interest in Harris began with Lucy Harris, the daughter of Mark Harris and Elizabeth Honeybunn, who was born and baptized in 1842 in Navestock, which is a rural village close to Romford and Barking. Working back through three Navestock generations I got to Stapleford Tawney, Bloomfield and finally lost track in Boreham in the early 18th century; they were poor agricultural labourers who I assume moved to wherever the work was.
During my trawls through many of the parish records of Barking, Romford and numerous surrounding settlements while researching various other family branches, I have recorded the baptisms, marriages and burials of some 448 individual Harris family members, just in case I accidentally pick up the thread again. There are several mid 18th century Josephs among those from the Barking (not Barkingside) registers. If you are interested in those, or my entire list of Essex Harris family members, please PM me your email address and I'll send it to you (it's an MS Excel file).
Steve.