if bedtime is roughly 12 hours after get up time, the last nap should in my experience finish about 1.5 hours before bedtime. If you then follow with a set routine (mine LO has naked kick time for 10 mins etc whilst I run her bath, then bath, dress, feed and bed. I start that around 6 and aim to be putting her in the cot at 7. sometimes she is still too tired to eat fully even after the nap, so that latest is 7. I also find if she is too tired when she goes down, we get more phantom crying etc in the first 1.5 hours
Funnily enough she also woke 1.5 hours after bedtime last night - cried hard so I went in and to me it had all the appearaances of a bad dream! As soon as she saw me and I let her suck on a dummy (only has it on odd occasions) she went back to sleep - maybe your LO dreams too!
If it is regular lick clockwork, you may want to try the wake to sleep method. Gently stir LO about 40 mins into his sleep - you know best how much or little to stir him, so that he responds (movemement or a noise) without actually waking him...hope it helps..