She's 21 mo.
Until recently that was her routine:
Wake up around 7.30-8
Nap 2-4
Bed 8.30-9 (asleep in 10-15 minutes, happy to be left alone with a book and toys)
Last week or so, she will not fall asleep til almost 11 
- even if put in her cot by 9.
Today she refused to go for her nap (bf, fell asleep, woke up when put in a cot, didn't go back to sleep).
So I thought, ok, no nap, but will put her to bed at 8.
She fell asleep in the stroller while we were out for about 40 minutes. I'm one hour ahead of the UK, so it's almost 11 and could still hear her chattering few minutes ago 
.
WWYD? Cancel the nap? But then she'll be v.cranky in the evening/falling asleep too early.
I didn't mind 9 pm bedtime, but 11 is not happening.