Someone had suggested that I go into his room ahead of when he wakes so that when he stirs I can pat him through the transition back to sleep.
At the first nap this morning he was already awake when I went in at 30mins, I patted for about 15 mins, he then slept for about 30mins more, again I patted for 15 mins and he slept for about 10 mins more. So down for about 1h40.
For the 2nd nap, went in after 30 mins and patted him through transition, he then made it through an hour on his own, heard him start up and thought no way am I going to be able to get him to go any longer but as I type this he has been asleep for about 10 mins taking this nap to a total of nearly 2 hrs so far.
So the good news is that it is possible to extend the naps. The bad news is it involves a lot of time sitting in his nursery.
I am in 2 minds as to whether I am setting him up to need me to get back to sleep. However when I was leaving him to settle himself he very rarely did. At least this way I am hopefully creating the pattern of longer sleeps and in time he will naturally do this himself.
I do at least feel reassured that my assessment that he needed more sleep was accurate as he surely would not be so easily patted back to sleep if he was really ready to be awake?