Notes for Geffry Dormer
Their third son was Sir Michael Dormer, lord mayor of London 1541-2 (William must have died rather young, though after five children).
Arms Generally notes for Geffry Dormer
The arms of Dormer from the 1634 visitation are:
Azure (blue), billety, on a chief or a demi-lion rampant, issuant sable.
And this is illustrated by John Withie on p. 14 of his Arms of the Aldermen of Aldersgate, compiled in 1616 and published in 1878.