hmmm this sounds a bit like our DD.... she would never sleep in her cot until about 10.30pm at night.... she would be tired from 7pm onwards, but just plain refused to settle in her cot... so she usually slept in my arms while i sat on the couch etc, but come 10.30pm for some reason she would fall into a deep sleep...

im sorry i probably dont have much advice for you, as they are all so different, and what works for one doesn't for another, IYKWIM.

we do manage to get her down at 7pm ish now, and the aim is to give her a sleepy feed at around 10pm, she will then make it thru the night without a feed until morning, but it is touch and go as to whether this works... sometimes she takes the feed at 10pm and goes back to sleep no worries, other times i feel i should have just left her alone and fed her in the middle of the night, as she is unsettled possibly with wind after the 10pm feed and i have to resort to taking her into bed with me and cuddling her, meaning we both get a bad nights sleep.

one thing i am doing at the moment which appears to have made all the difference is in relation to her day time sleeps... the aim is for her to have a big sleep in the morning (1.5 to 2 hours) then another one in the early afternoon, say starting at 1pm... then i only let her have a short catnap (if i can get her to at all) in the afternoon around 4pm... so she is awake from about 4.30pm-5pm after only having a short nap to take the edge off, so come 7pm she is quite tired and ready for bed.... it took a while for this to fall into place though...

she will usually have a good sleep in the morning, then its touch and go how she sleeps in the afternoon, sometimes well, other times just short cat naps.... apparently 'they' say that a nap 45 minutes or less doesn't really count as a proper sleep as it is only one sleep cycle, and it will merely 'take the edge off' and buy time.... (this is what i have read, it seems to be the case with my dd).... the only thing i can possibly suggest, is that you try to get him to have a bigger sleep in the morning, then shorter sleeps in the afternoon, so he is ready for a sleep at 7pm ish... i would try this for a few days, as it can be hard to change sleep habits.... of course it may be disasterous, but it seems like it is worth a shot, as he is already so unsettled it probably can't get much worse...

but they are all different so who knows... it is such an experiment. i hope things change for you, i know exactly how u are feeling.