Thanks all
Haven't done the heat/cold thing - I never quite know what's best and last time I tried a heat patch it seemed to make it slightly worse (or was just coincidental with it getting worse anyway).
Will definitely have painkillers and a drink to hand for when i wake - am getting an early night and settin the alarm for 6am to give myself time to get ready slowly with the help of the painkillers.
On the upside, I managed to do all the prep I had intended to do and having done a full read through I'm a little happier with the thesis than I was a few weeks ago.