Back again.
I don't think you need to cut out the am nap all in one go. When ds was 12m I started adult ed classes two mornings a week, so he missed his am nap twice a week. He usually fell asleep on the way home, but not for long and not always. The rest of the week he had his am nap as normal. Then I gradually dropped it. Even now, he's 3.5 and still naps in the afternoon, but can cope with missing the nap one or two days in a row.
I don't remember whether ds slept longer at the pm nap when he dropped the am one. The other day dd slept over 3 hours after an 11ish lunch, but she hasn't repeated the feat! She used to sleep 1 - 1.5h am nap, and 1.5 - 2h pm nap, unlike ds who could, and still can, sleep for England, night or day. What I would like her to do, if she no longer needs the am nap, is to sleep for 2-3h in one block, because that's what I think she still needs. Unfortunately, being ready for a nap at 11am (which is what happened today, and is what usually happens now) means that she is unlikely to go down for another nap in the day, so by about 4pm she gets so worked up that I have to either carry her around, or leave her screaming. Children's supper here starts 5 - 5.30pm, bath about 6.15, and bed about 7.15. I'd make bath and bed both a little earlier, but they're dh's main contact with the babies during the week. The bath seems to rejuvenate her, and she becomes her usual cheery self, even if she hasn't napped enough. (It's only on weekends that dh sees what she's really like without enough sleep! )
Fortunately, once she's in bed for the night, we rarely have to go to her again, though we generally hear plenty of groaning and occasionally a little crying. She wakes any time from about 5.45 to 7am, 6.30 being about average.