It could be that he is stirring a little bit and then thinking "I could watch my dvd if I wake up". Hard as it will be I do think you will get success if you don't let him do anything other than "night time things", so treat that 5am WU as a night waking. Keeping him in bed and doing whatever you would do to sleep train him into staying fete until morning that you would normally do if he woke at say 1/2am.
This will be hard to begin with so you might need to start off by agreeing that morning is actually 5.30 ish, keeping it early to make it achievable. So you do the NW treatment until 5.30 and then leave him, come back in and say "it's morning". And then get up and start the day. I would suggest no DVD at that point too, to help him understand waking up doesn't mean TV.
I would stick with what you're doing re naps, I do think there would be merit in bringing BT earlier. I do understand wanting to have some time with him when you get in from work, but this may well be keeping him up beyond his sleep window and he may be OT when he goes to sleep, this would make EWs more likely.
Another idea - have you ever tried wake 2 sleep (W2S).
How do I address habitual wakings? (wake-to-sleep and other methods)I would keep consistent on this plan for another week though - it can take a while for an LO to adjust and changing too much too soon will make it hard to see what might make a difference.
((Hugs))
