Flintoff, who entered the ring wearing the shirt of his county cricket club Lancashire, had the better of the exchanges in the opening round, but was knocked to the canvas by the 23-year-old Dawson during the second.
Liam Botham, son of England cricket legend Ian, will wear an England shirt for the first time and is joined by the uncapped centres Leon Lloyd and Ben Johnston, fly-half Ali Hepher, scrum-half Martyn Wood, flanker Paul Volley, lock Steve Borthwick and loosehead prop David Flatman.