Hi Dinkey
We are talking about a baptism of Joseph in 1812 and a marriage before that. As you are probably aware, if Joseph was their first child, then daughter very often went home to mum to have that first baby.
In 1812, there was no public transport, (Trains came in 1840's) so everything had to be within walking distance - so you need to look within walking distance of Milnrow, Nr Rochdale for their parents, marriage and baptisms, etc.
The IGI at best only covered 45% of the country (many churches would not release their Parish Registers for the Mormons to transcribe) and is to be used as a finding aid only - the parish registers must be checked to verify the data contained within the IGI.
A lot of the information in the IGI came from Bishops Transcripts - i.e the copies of the registers that were done at Easter each year by the church clerk / warden (unpaid job) and sent on to the Bishop; so already we have a copy of the original - mistakes in copying did / do happen. They started on one line, and finished off on the next line because their finger slipped, or else there was nothing in the register because no one had filled it in, so the transcript for the Bishop was completed from memory.
So, I do not believe they are anywhere in the country, my bet is that they are within a 5 / 10 mile radius of Rochdale.
Chris in 1066Land