Ok, thanks Gordon. I'll re-pitch. Crashing the temp was a mistake - had no idea the cooler I made (idea taken from a thread on this forum) would work so damn well!! The yeast is about one month old, been sitting in my fridge...should still be good, right? I added some nutrient originally. I aerated by allowing cooled wort to pour from kettle into fermenting bucket below, through a strainer - seemed to aerate well.
Enjoyed your book.