Wouldn't this be one where it's worth investing in the birthcertificate you refer to ?
Both questions you raise would be answered.
If you don't have this, and you have the mother's name from a census, then she just might be a second wife
Ignore this:- I've now seen the 1861 census
There are three Male Machell deaths on Free B M D for 1845/1861 David & Two Georges.
But I couldn't find a Manchester Marriage for either of these names on Free B M D or on Lancs B M D