Dust jacket, The Book of common prayer: the texts of 1549, 1559, and 1662, ed. Brian Cummings (Oxford: Oxford University Press, 2011):
All of the prayers in the 1662 BCP invoking "a creator" are at the very least binitarian. And the Thirty-Nine Articles as published in that same edition are pretty specific. Take just Article 1, for example:
There is but one living and true God, everlasting, without body, parts, or passions; of infinite power, wisdom, and goodness; the maker and preserver of all things both visible and invisible. And in unity of this Godhead there be three persons, of one substance, power, and eternity; the Father, the Son, and the Holy Ghost.