"WoW! Calvinists using a Church of England form of Confession."
The founders (Cranmer, Ridley, Hooker, et al.) of the Church of England, AND its founding documents (original Book of Common Prayer, and the 39 Articles) were very Calvinist, actually.
Don't forget that the Westminster Confession was also a creation of C of E divines (dominated by the Puritans at that time, admittedly) even if never adopted by the C of E.
The form of confession in question was drafted by an Anglo-Catholic in the Church of England which makes it even more of a WoW! than at first glance.