I'm unable to decide if I should be worried about this or not, as GB never usually lies down in the field, he just stands and dozes. (This to the extent that, when we got back from Loncon, Mrs Next Door told us with concern that she's seen him lying down. We diagnosed at the time that it was because his bed wasn't being done properly, and he doesn't like to lie down on dirty bedding, so he was having to catch up on his sleep in the field.)
He's been doing it, on and off, for a few weeks, and I had thought that the cold might be keeping him awake. It's warmer now, though, so I worry that it's a sign his leg (or some other ache or pain) is bothering him.
Mike's work have been asking him to do two days a week in London (again: when he first started they wanted him to do two days and offered to pay for a hotel room in between), so he's trying it as an experiment for the next couple of months. He's been there today and was going to go to the Ton until he had a migraine start: he's had to give in to the inevitable 4am waking up and has taken himself to bed.