Robert Withers Cambridge Early 1800 S

I am looking for birth records for my ancestor Robert Withers.

He was married twice, his 2nd wife was my ancestor, Ann Hillam. They lived in Wimpole, Cambridge where he was the land agent for Wimpole Hall from 1815-1837. They had five children: Ann, Charles Robert, Henry Alfred, Edmund, and Arthur. Robert also had a daughter, Sarah Rebecca Withers from his first marriage, whose mother apparently died in childbirth.

He is listed on his marriage certificate as being from Orwell, Cambridgeshire, but I have been unable to find any record of his birth so far.

Any information on any Withers from this era would be greatly appreciated!