I'm really not that great with specific A times, but at this age 15 mins difference in A time is really not going to make a huge difference. We are not talking about a little baby here! I would try for an 11hr day if you have no nap, see how that goes. I don't think the 5.30am NW is UT, especially as he went back to sleep for 1.5hrs! UT would tend to be difficult settling, or long happy NWs in the middle of the night.