Transition from 2 to 1 nap

My son is 14 months in 4 days and I think he’s in the middle of transitioning from 2 to 1 nap. If he wakes before 7 he has 2 naps but if he wakes at 7 or after I’ve recently had to force him to stay awake for longer and just have the 1 nap as the second nap would then run into the time I have to pick my eldest up from school. I hve noticed though that sometimes he wakes quite a lot through the night if he has the 1 nap so I’m not sure if that’s because he’s over tired? Am I doing the right thing?