Green with the Union Jack occupying one quarter of the field and placed in the canton and a harp in the fly.
This flag has appeared in these historical flag plates:
1685 Downman's Flag Chart
17th century A New Table of all the Ships, Collors or Ensings, in the Wholl Water World Newly Eneressed and Amende and all falts or Errors Corrected Never befor thytim brought to Light[2]
1700 Len's Flag Chart
c. 1700Table des Pavillons quel on arbore dans toutes les Parties du Monde Connu (Peter Schenk the Elder)[3]
early 18th century: A new table of all the names of the principal parts and rigging of a man of war[4]
1772 French Encyclopédie
1783 Bowles's Universal Display of the Naval Flags of all Nations