Hi - I'm not sure if you still need any help with this, but I think I have found John & Elizabeth in 1841 in Rothwell Northants (wrongly transcribe on An**y) as Bilsam
HO107- 809 Bk 17
Parish Rothwell
So it seems as though they were married by then - this marriage from Free BMD looks possible to me
Marriages Dec 1840
BILSDON John Mt Harbor 15 257
CLARKE Elizabeth Mt. Harbro 15 257
GOODWIN Harriet Mt. Harbro 15 257
HOBBS Elizabeth Market Harborough 15 257
Page George Mt. Harbro' 15 257
PALMER William Mt. Harbro 15 257
Tea Sarah Mt. Harbro 15 257
WADDSWORTH William Mkt HArbro 15 257
Do you have any of the childrens birth certificates to give you the mother's maiden name? If not you can still send for the marriage certificate - but only fill out the Grooms details on the aplication, if it is the right one it will give you both their fathers.

DebbieG