Time for a little update on Blue's nocturnal habits, just in case this is useful for anyone else having puppy sleep issues. I slept on the kitchen floor for a few nights, moving slowly further away from the crate until he could hear me but not see me. Blue was fine with this arrangement, but I had a couple of very bad nights myself, with severe cramp and hip troubles, so it was essential that I got back to my bed sooner rather than later.
So 3 nights ago I waited until he was settled in his crate and then I went up to bed. The first night I set my alarm for 4am, which is when he usually starts moving around. I actually made it downstairs just as he was stirring, and it was perfect! He went straight out to toilet, and then settled back to sleep with me on the sofa.
Second night, I planned to repeat the same routine, but he woke us first at half past midnight. I got up to sort him out - he'd soiled and trod in it, but he went back to sleep within half an hour, and I went back to bed.
Last night, same again. Up briefly at quarteer to one, I went down and settled him (no soiling this time

) and was back in bed within 20 mins, and I got up again at 4. Looks like this will be the new routine for a bit, maybe until the mornings start to get darker, but at least I am able to get some decent sleep in my bed, I'm too old for sleeping on the floor, that's for sure!