The 1891 English census SHOULD have listed info from which you could estimate his DOB +/- 2 yrs. You should have listed this info.
For Pat(rick) Cronin M 1857 (exact), somewhere in Ireland, I found 4 rcds: 3-Cork, and Limerick. A view of one or more of these M rcds should reveal the parents' names. This will validate which, if any, rcd is for this ancestor.
If validated, then you can start looking for Pat(rick)'s B rcd ca 1832, or some other date computed from info on the M rcd.