Too early to go to one nap?

Max is 9.5 months now and I am really struggling to get him to have his second nap since we have been on holiday, but he is sleeping more on a night, on holiday he was doing this-

6:30-Sleepy breastfeed
11:30am- 20 minute nap
12- Lunch
4pm- 2 hour sleep
8:30-9 sleep

Since we have got back he has continued to fall asleep after his breastfeed first thing so is pretty much sleeping 7pm til near enough 8am, then he wants to be asleep at 10:30/11 for a couple of hours, then I have been trying to get him back to sleep 3 hours after waking but he is fighting it like mad, today he was up from 12pm til 7pm!! The only time he was grumpy was when I was trying to get him to sleep, I got him off twice and he just woke up five minutes later! Surely he is too little to be up that long?

Any suggestions to our routine would be appreciated!