Hi there!
Here's a useful link re the 2-1 transition:
From 2 to 1 nap transition (10-12m and older)10 mo is still quite young to only take 1 nap and there is a risk of OT creeping in if that is your pattern for more than a couple of days.
Your options when the nap gets so close to the middle of the day are:
1) Try to squeeze in a very short catnap (even as short as 15-20 mins) around 4/4.30. Sometimes it's easier/possible to AP this in the buggy/pram/car. This can be enough to get to normal BT, avoid OT and maintain night sleep.
2) if you can't get your LO to CN, move bedtime much earlier, my DD would normally have BT around 7-7.30 but during the 2-1 transition went to sleep as early as 6pm.
3) You may find you get a mix of one and 2 nap days. This seems to help avoid OT. My DD did alternate 1 & 2 nap days from around 10-11 mo but didn't transition to only 1 nap consistently until around 13mo.
HTH. Come back if you want to chat through.
