I just found them in the cupboard, having gone rock hard. The initial reason for buying them was to put them in the microwave to see what happened, as when doec sent me some the instructions clearly said to microwave them.
So I thought, "Well, they can't get any worse."
Dude. Stale cookies zapped for 45 seconds on full power? Chocolate heaven! The edges of the cookie are all crispy and the chocolate's just started to melt...