Do you think he might like wrapping? We had a lot of issues with DS2 at around that age with sleep and one night I decided to wrap him and we had a full nights sleep. I didn't think of it earlier because none of mine ever really liked wrapping and certainly not at that age! Could you try reading to him in bed, get him nice and relaxed, use a dim light to read by so the room isnt' so bright and then just sit with him, beside the cot and just put a gentle hand on him to keep him in the one spot. We had more sleep issues with DS2 about a year ago now and he flat out refused to sleep in his cot and it got beyond a joke and I decided right, no more of this so we put the cot back in our room (we'd moved it in with DS1) and every night I would put him in bed by 8pm, turn the light off, turn the small tv on in our room with the sound muted so there was light and just sat beside him with my hand on him. The first few nights he cried a lot because he wanted to get out, but I was always there with a gentle hand on his shoulder. The first night took nearly an hour for him to go to sleep. He wasn't crying for that entire time though, he settled but was just awake kwim? I couldn't leave the room till he was fully asleep either. by the end of the second week I was able to say to him, 'ok, I have to go do xyz, I will be back in a minute' and after 5-10 mins I would go back and check on him and 9 times out of 10 he would be asleep and within a month I was able to put him to bed awake and leave him there. It really helped doing it at the exact same time each night too. Even if you don't have a routine as such during the day, having one at night might help and get him clued in that its nighttime and time for him to wind down and go to sleep. I hope it doesn't last much longer for you though.