Finally decided to let the cat sleep with us last night with warnings of what I would do if he poked me in the mouth to wake me at 4am.
10 minutes after lights out the miaowing started so I went to set the utility room up for him & he was sitting on his blanket waiting for me to finish.
Tonight he's going down as usual, probably with the customary miaow of "but I don't want to go to bed"