Hi Karen,
I can't help with the birth record for Job but it does seem probable that Job's parents were Joseph & Mary. There is a Robert Allen born about 1811 in the 1841 Census in Brimington so it likely that both Job and Robert were sons born in Brimington before the earliest surviving records for the parish.
Amongst the record collections on FindMyPast there are the 'Staffordshire, Dioceses Of Lichfield and Coventry Wills and Probate 1521-1860' and a record for a will made in 1826 by a Joseph Allen of Brimington. One of the executors at probate is Joseph's widow Mary. The will does not name the children as they are not of age but it does name Joseph's brother Robert and, unusually, his father, also a Robert who died in 1809. Worth a look.