@MrsJW15 Well I'm not sure how much was what we tried and how much was just him getting to the 3 month less narky bit. From speaking to others they do seem to go through a phase around 10 weeks of only wanting to sleep on you, not in bed.
Sorry for long explanation but this is basically what I did, not saying it's a solution for every baba at all...
But I would wait for the VERY first sign of sleepiness, a tiny yawn or whatever and immediately do quiet cuddle or song. It almost always happens for him about 2 hours after last waking up. Tiggerbaba likes to lie in my lap on his side in a sort of bf cradle position (prob comfy as has acid reflux) and I'd wrap a blanket over his back, wait til he was almost asleep then gently lay him down on his back, first on my knee then in bed. The blanky is warm on his back so he doesn't get the cold shock as much when I put him in bed! (I also warm his bed at night with a warm hot water bottle, really works for him) If he wakes when I lay him down I just put my hand on his tummy and smile and either chat quietly or shush til he drops off. If he cried I'd pick him back up, cuddle til happy then repeat. It meant staying by him and doing it sometimes for ages, but it only took a few days before he'd sleep quicker and he often settles himself now, even if pretty much wide awake sometimes. I think it helps that when he stirs to wake I make sure I'm right there to say hello and he sees me almost straight away.
I do think sleep breeds sleep, we've had some really hard weeks where he literally wouldn't sleep all day from 11 am.
I feel your pain. Afternoons were NOT FUN!
@CoxsOrangePippin yes it's a total pain when they can't find the thumb! They get better at it though