Most people do look ups because they enjoy doing them,
not because they have any connections to the family being researched.
Speaking personally I tend to get more involved if it's a parish that I'm conversant with, Langford being a case in point.
I know nothing about Sheep Lane so leave it to those with local knowledge, like Tazzie.
His age in 1851 points to a birth c1776 as you said in your first post, and as there's no baptism on the IGI in Beds at around that time, you're struggling for any clues you can find. So my post of 12.13 yesterday remains pertinent - you need to check the parish registers for both marriages to see if there is anything which might help
Regards
David
Messages have crossed in cyberspace so I'll add a bit more in light of your post a moment ago. A FHC is your best bet. You can order microfilms of many different parishes but you can normally only do this in person, not by post or phone.