Couldn't read this and not reply as the routine your son has is identical to what my sons was. He didn't drop to one nap until 20months! It was the only thing that helped. I gave him 5.5 hrs either side of the nap and bed around 7pm. Sometimes earlier. We got him a groclock and at 24months he finally started sleeping 11+ hrs a night again and stayed asleep until 6, earliest, even 7:30 these days. He's 2.5 now. The clock really was the only thing o solve the Ew, he would want out of bed as early as 4:30, sometimes 4, but with the clock he quickly learnt to wait quietly, and began going back to sleep! As you probably know that's rare for an Ew toddler! I'm not of much use really, but hope you find something that works too. My Lo is ill at the minute and waking at 6, so I too am dreading the 5am start tomorrow. But I remember from last year it doesn't take long to work itself out.XX