Just started waking up at 6am

[thawley]

My LO is 11.5 months old (8.5 corrected).  He is a great sleeper always has been but has just this week started waking up an hour early.
It doesn't matter what time we put him down he wakes up at 6am.  The first night he went down at 6:30 and woke up at 6.
The next night he went to bed at 7:30 and woke up at 6.  Last night he was in bed at 7 and was up at 6.  It is 6am on the nose and seems to have become a habit.
How can I work on getting him sleeping until 7am again?

His schedule this week looks something like this:

6am wake up (this used to be sleep until 7am)
7am - bottle and solids
9am nap for 2 hrs.
11am bottle then solids
2pm nap for 2 hours
4pm bottle then solids
then bath, bottle and bed by 7pm

We target bed around 3 hours after last nap so hence the reason his bed time changed a few times this week. 
This has always been how we have done his bedtime and it has never resulted in early waking.

[Sarah - Enfys' Mum]

Does he always nap for 2 hours morning and afternoon?  Could it be maybe you could decrease that a bit?  He might be waking up at 6 because he's just had enough rest.  Also, is he crying?  Or just awake?  If he's just awake, I would leave him in bed as he may fall back to sleep.  My dd is a chronic early waker and I've decided that 6.30 is get out of bed time.  If she wakes up early, she plays with herself for a little while and if she gets upset I go in and pat her back.  She very rarely goes back to sleep though   And the other thing I do is I never let her nap in the morning before 9, you might want to try the same - pick a time for morning nap and try to delay putting him to bed till then. 

[thawley]

Yesterday his afternoon nap was short (which rarely happens).  I thought that perhaps that meant he would sleep past 6am but no luck. 
I try to leave him in his crib for as long as he will go without getting too upset.  He doesn't wake up crying.

[Sarah - Enfys' Mum]

I'm curious - your ds was quite premature, but is now 11.5 months - when will he "catch up"?  Does that make sense.
I'm still thinking he needs more A time, but I would add it to the start of his day, so maybe delay his first nap by 15 minutes or so to start with?  I know all lo's are different, but my dd is 9 months old and regularly does 3.5hr or more A times.

[thawley]

I think they expect him to catch up by 2 years.  Right now developmentally he is fairly close to his corrected age.
I'll try more A time and see if that helps. 

Thanks!