The Allens should have come from Coventry, but have been traced to Norton Juxta Twycross in Leicestershire.

My mother's real maiden name was Allen, although she was known by her foster mother's name, Wood.
I was told by my great aunt Mary Ellen Birkbeck that she once met a cousin of her father's, Joseph Howard Allen, who told her that the Allens were an old Coventry family, but as yet I have not managed to trace them to that ancient city. Joseph Howard is also a mystery, I know lots about him but not where he was born or who his parents were.

Meanings:-
From Allen, a common personal name at the time of the Norman conquest. Widely distributed, excepting Northumberland and rare also in the northern counties beyond the Humber and the Mersey and the southern, western counties of England. Most common in Derby, Hants, Leicestershire, Rutland, Lincolnshire and Suffolk. (The House of Family Names, H.B.Guppy)

Kingsbury Church Font - Many Allens were christened here. This font dates from the 14th century, and has a twelve sided basin raised on hexagonal stem.