Having had massive amounts of sleep, I am feeling surprisingly improved. Is it OK if I make a decision based on what sort of pace feels sensible on the commute tomorrow morning? To be fair, last year I did my first 100km audax, and got round comfortably in time, feeling rather worse than I do this evening. But I am acutely aware that I am very likely to be the slowest person on the list for this one - and there's a limit to how big a margin is reasonable!
I have also very much prioritised sleep over any thoughts of baking, so there's a distinct dearth of CrinklyCake for this one.
ETA
Half an hour, door to door, to site - about 6 annahalf pancake flat miles. I wasn't really pushing, it didn't feel like hard work apart from the bit where I hammered it because of the blind bends and the queue behind me.