OK, so after receiving the email, I sent a copy to my SIL with the comment that often times, I will pay a greatly reduced rate versus using points.
With her Brittish hubby, they travel to England enough and sure enough, when she checked the link in addition to being £10.00 cheaper than their existing reservation, it included breakfast.
When she logged in to her account to book the room under the promo, the rate jumped £20.00 without breakfast; in effect, £10.00 higher than her old reservation!
Some sale!
She is caling the Diamond desk to find out what the hell is going on.
Update: Just got her email, they honored the lowest rate with breakfast.