Thank you both.
He was 1 month prem so his adjusted age is 7 months, but I don't suppose the A time should be much different. I always thought around 3 hrs was the norm for 6-8months. I have considered longer A time but, particularly after WU, he gets really grumpy after 2.5hours and the stretch to 3 hours can often be a struggle!
His current as times are around 2.5-3hrs after WU, then he can often go a bit longer than 3hrs until his pm nap, then it's normally 4hrs until BT.
An average day looks like this:
5:30am WU (I aim for 6:30, he can usualynresettle until 6ish... but recently we have been getting a lot of EWs)
E 06:15 (bottle)
E 8:00 (solids)
S 8:30 (1-1.5hrs with resettles)
E 10:30/11:00 (bottle - doesn't always want this)
E 12:30 (solids)
S 13:00 (1-1.5hrs with resettles)
E 15:00 (bottle- doesn't always want this)
E 17:00 (solids)
E 18:15 (bottle)
S BT 18:30
He then wakes frequently at night - a couple of dummy calls (which is a separate issue) but then from 4am he needs resettling every 15-20mins usually and from 5am/5:30am seems to have had enough and just wants to get up.
A couple of times every few weeks he will sleeps 10-11hours straight through from BT. But these days will be seemingly no different to any other!
For naps, I do go in just before his sleep cycle ends and sssh/pat to see him through to the next cycle. It normally takes 10mins to get him fully settled again. It works most of the time to extend to 1 hour. Sometimes I can do a second resettle but that doesn't always work. Sometimes I have to hold him instead, if sssh/pat isn't working and I can tell he's still tired. I've been doing this (W2S kind of method I suppose - although I don't purposely wake him, I wait until he stirs) for over a month now and seen no improvement. If I leave him to nap completely independently because a) I'm busy or b) we are not at home, he will still wake up after 30mins.
When he HAS napped for longer by himself, there is no pattern. Sometimes am nap, sometimes pm nap, busy days, quiet days, sometimes after 2 hours A time and sometimes 3+ hrs...
He self settles for all naps and at BT with almost no fussing. And as I've said, has slept longer for naps and at night.
With regards to allergies - we are very careful with his dietary requirements and I'm almost positive he would not have consumed any dairy. Particularly as this is an ongoing issue, this would mean he's eating it all the time. He may have undiagnosed allergies to other products, but no more so than any other child. Having suffered with misdiagnosis for 6 months, i tend to recognise the signs of a bad tummy for him and this is not happening a majority of the times I'm referring to.
Sorry for such a long reply! Just trying to answer all questions and paint the picture!