This Sunday is peculiar:
In a year when there are 23 Sundays after Trinity before the Fourth Sunday before Advent, the Collect and Post Communion for the Last Sunday after Trinity shall be used on the 23rd Sunday after Trinity and the Collect and Post Communion for the 3rd Sunday before Lent shall be used on the 22nd Sunday after Trinity.
From the Church of England's Rules to Order the Christian Year.
So now we know!