The Bodleian copy printed by Pitts is given the approx. date range of 1819-1844 (Harding BH11(38)). This was posted early in this thread.

Jack Reeve, comic singer, also performed Billy Barlow, c. 1836. Thread 62999, Lyr. Add: Billy Barlow.

I can't find a John Valentine, composer, in early 19th C., but an earlier John Valentine, perhaps antecedent, is discussed in Karl Kroeger, 1988, John Valentine: Eighteenth-Century Music Master in the English Midlands, Notes, 2nd Ser., vol. 44, no. 3 (Mar. 1988), pp. 444-455. Other members of the family, I believe, are discussed.
I don't have access to that journal.