Hello Clive(Your Darvill@tinyworld.co.uk
While digging up my own family history I came across your post.
My paternal grandmother, Emily Lillian May Darvill (b. 1907, registered in Rochford) was daughter to a Charles Darvill, possibly born 1856.
They were in East London/Essex area, at least when my grandmother got married! :-)
I don't have any family mention of a James Fredrick, though;
She supposedly had several siblings: Walter?, May?, Eli?, Alice?. James?
If we share the same great grandfather, Charles Darvill, then our fathers would have been cousins! :-)