Hooray! I've found the secret to getting jack to take long naps! Plan to go out! Wanted to take J to get weighed this morning, clinic finishes in 5 minutes and he's 1hr 15 into a nap!
Seriously though, not sure what it means but pd at 3 hrs 40 again today (made sure we weren't slightly early like yesterday) and it's finally worked! We had a good night last night as well. He had a rare 12 hour night, with one nf and he woke at 5.45 am and resettled himself which has literally never happened at that time of the morning! I put him down after 2 hrs 50 in the end last night so maybe he needed a lower A time before bed like you both said? Anyway, no idea what A time to try for his afternoon nap now but I'll try and keep the A before bed to around 3 hours if he has a good nap, or 2 hrs 45 if he has a short nap do you think?
Thank you for all your help so far
ETA: He's just woken now after 1hr 20