I have good news & bad news.
There's a rich guy in our line of Allen's -
Sir John Alleyn of the Mote, Lord Mayor of London
And his parents look correct.
BUT I suspect his grandparents
Lord Sir Thomas Alleyne "the Elder," of Outwell & Margaret Alleyne
Because
1) Norfolk is not Essex
2) there are some alternates possible that may make more sense in spawning a mercer & alderman of London - such as a
Richard Aleyn Alleyne "Gent" City of London Guilds - Worshipful Co Of Dyers.
Birth abt 1455 in Thaxtead Essex and London
Death 1508 in bur. Thaxtead Church (St Catherine's Chapel)
http://trees.Ancestry.com.au/tree/11036604/person/6134341124
Opinions please!