Ok so yesterday I was able to get them down for a second nap after 3.5 a time and they slept about 50mins - I know I probably should've woken them

J asleep by 6.45pm
woke around 1am and very unsettled. Not crying but faffing and tossing and turning (getting worried as this is what O used to do for hours on end...) I finally fed him at 2am and gave him some calpol he slept till 6.30am
H asleep 7.10pm
woke at 4.15am - fed and back to sleep woke at 5.45am
TODAY
nap 9.40 H slept 1hr 15mins, J woke after 50mins but went back to sleep with some apop for another 40mins
then H fell asleep in the car after an a time of 2.5hrs

he slept 50mins
J fell asleep 10 mins later (he obviously got up later so still about 2.5hrs a) and slept 30mins.
So both boys have been awake since 2.15pm
H is a grouch and has been all day, I think he's suffering in the heat but he's also cutting a tooth.
So will be interesting to see what happens tonight. They can't go down earlier cos DH is at work.