The dreaded early morning wake up!

[getoffthecoffeetable]

DS is nearly 23 months old. Was previously sleeping 6.45pm-6.45am up until around 6 months ago. In the intervening period we've put him in a bed because he kept climbing out of his cot. He loves his bed and wasn't upset when we ditched the cot. Anyway, he's normally a happy boy except in a morning when he's tired and he wakes up crying.
We never leave him to cry it out and use the put back method with varying success in the morning. He usually wakes up between 5 and 5.20am.
I've tried putting his bedtime back later but if anything, this causes him to wake even earlier.
He has a 60-75 min nap around 1 and I honestly don't think he could drop this yet because he's really tired by this stage. When he's at nursery he just falls asleep by 1.
When he wakes up, he's crying and still tired so I do think it's not that he's just an early riser.
Any helpful hints gratefully received. Sorry it's so long.

Ok, couple of options which might be worth a try:
Reduce the lunchtime nap to say 40 mins? My oldest dropped all naps at 25 months, so it is possible. Or try some days without naps, but quiet time on the sofa, and naps other days.
Take him into bed with you at 5am, and see if he'll drop back off, and let you snooze.
Put him to bed earlier? Maybe he needs more sleep?
Try a carb rich snack just before bed (bowl of cereal, slice of toast) to ensure he's not waking up hungry?
Shift his whole day by and hour - so, breakfast, lunch, nap, dinner, bedtime all move by an hour, and hope morning wakings follow?

Good luck - starting your day at that hour is awful - tho tesco is quiet, if you can bare to go out and use the time productively!

Thank you nextphase I'll give it all a go, although obviously can't do anything about the nursery nap.
Don't think I could face shopping so early. I tried it once and he cried the whole way there!
I'd been wondering if maybe he was overtired or I needed to change his nap.
Fingers crossed!

Of course you can do something about the nursery nap!
You pay them. Ours are under instruction to try and wake him after 90 mins, and no way to let him sleep over 2 hrs, or after 3pm.

You're right. Of course I can. Sorry. Sometimes need the obvious pointing out that's what early mornings do to me!