Well, first of all - well done with the DF, this is really good news and I hope it is useful to you in future.
Gave DF meds at 2am - worked fine, barely stirred
WU 5.45S 9.55-10.25S 1.15-2.45 (woke up after 45 mins, had to APOP)Bed 7 - fell asleep fine, gave meds before bedNW - 10pm - managed to just lie down and SSNW - 10.20 - had to go in a few times to lie down but SS and back asleep by 10.45
Looking at this in isolation, I do think that it could be that the early nap is causing him to wake up earlier in the morning. It's as if his body knows he can get sleep again soon so he stirs in lighter sleep and isn't quite tired enough to resettle, even though he does need a bit more sleep really.
He was probably pretty tired by that first nap after 4hrs A time, but then he seemed UT for the second nap, perhaps a little later for the second nap in the afternoon would help.
At this age we had to go to set-naps for E and it really helped us get over the early starts. But, it did mean a good couple of weeks of her being really OT while settling into the new pattern. Also, if you decided to try this, you would need to decide what pattern to follow and stick to it. It would seem that one nap at 12.30ish would be a good start and I would hope that this would enable him to sleep longer in the morning.
However, as you might need to allow for a short morning CN and longer nap in the afternoon on days when you pick him up from nursery at 1 it might take longer than normal for him to settle into the pattern. On those days could he do a very short CN at nursery (say 20 mins) and then wait until after you get home to go down for a nap?
Have you read this?
Set naps for toddlers: Why, How and WhenWhat do you think?