[2][3][4][5] Allen was educated at the Free Grammar School, Manchester and at Trinity College, Cambridge (admitted 1788, scholar and prizeman, graduated B.A.
He was appointed a prebendary of Westminster Abbey on 4 October 1806[7] which appointment he held until 1836, vicar of Battersea in 1808 (Battersea was in the gift of Lord Spencer) and vicar of St Bride's, Fleet Street in 1829.
The fact that Allen held more than one living at the same time was not uncommon in the eighteenth and nineteenth centuries.
It was during Allen's episcopate (in 1837) that the Counties of Huntingdon and Bedford, and the Archdeaconry of Sudbury were added to the Diocese.
By his wife Margaret Ashley (whom he married on 19 May 1807 at Frodsham, Cheshire),[10] Allen had three sons and a daughter:[11]