12 mo naps - one or two?

[Poocatcherchampion]

Current nap schedule is:

Wake up 0645 ish (I don't hear him until 0715 normally)
Nap 1 0915 after school run. Often doesn't sleep until 10 a.m. sleeps for 45 minutes. Nap 2 1300 hours. Falls asleep straight away. Sleeps for 45 mins.
Bedtime 1800 - falls asleep straight away sleeps all night.

He is always tired and basically just cries from about 4.30 til bedtime.

I thought it might be a good move to get shot of nap 1 and encourage a longer nap 2 but in 2 days so far he has only slept 45 mins all day so is even more knackered.

We are particularly buggered as nap one takes us to 11am, the 3yo has lunch at 12 noon and straight to bed for nearly 3h then it is school run. So we are basically stuck in all day every day.

Is there a better idea than mine?

At 12mo my DD was still having 2 naps.
Morning nap from 9:30-11 and afternoon 2:30-4, then bed at 7pm, usually slept through until 6:30am.
We didn't start the transition down to one nap until she was about 15mo. She's 17mo now and wakes at 6:30am, goes down for a nap at 11:30am and sleeps from then until anywhere between 1pm and 2pm! She's having a super nap today! I put her down at 11:30am and she's still sleeping now. She will have a bath around 6:30pm and be fast asleep by 7pm at the latest.
My only advice is not to rush the transition down to one nap. We tried too soon and the over-tiredness that ensued was a bloody nightmare! Her night time sleep went completely to rat shit as well

Overtiredness is def the problem here but I don't know how to solve it!!

Have you tried keeping him up in the morning by going out somewhere, for example? Just asking as my DD2 is only 10 months but can already go from 7am wake up until 12ish if we're going to playgroups, and then she has a 2 hour nap until 2/3pm. I'm not saying it's necessarily a better way, in fact I'd rather she slept in the morning and afternoon, but some days she doesn't seem tired enough for that. Having said that, if yours is overtired anyway I'd probably try and avoid going down to one nap just yet.

Yes I try but he still only sleeps 45min in the pm. I would continue the morning nap except he doesn't really seem to want it...