Ate the food, stayed awake to listen to the BBC World Service radio and look at the earthquake map on Richard's computer, and was back lying down in bed by the 3.30am news. Fell asleep pretty soon after and woke up at 9.15am. And feel properly awake now.
At least I am now awake at 9.33am, which is a reasonable hour for someone in my timezone to be awake. But that's a pretty stupid amount of sleep to apparently need.
Oh yes, since I forgot to record it here - all of my blood test results were utterly normal. My TSH, which has been elevated before, was 2.88 - that's within the normal range even by the stricter American standards! WTF is going on with my body? Might just be bog-standard ME/CFS. Joys.