hey dizzy
my LO is 10 mo too and we had some nap and EW trouble about 2 weeks ago which thank goodness seems to have sorted itself out now. i think it was to do with the 2 to 1 switch. it is a bit early but they start moving towards just 1 nap and needing less daytime sleep around this age. it's a tough age but you'll get it sorted out!
how much total daytime sleep is he getting now? what are his nights like? can he go to sleep independently?
my LO now is doing a long nap in the morning and a short nap in the afternoon (15 - 45 min, sometimes longer depending on the first nap and what time it is). usually around this time to limit sleep you do one or the other short, for us it works better to have the long one in the morning. also, A time for us is really varying a lot. between 3 to 5 hours. i used to be a clock watcher and now i have to go by cues (which is tough...). sometimes she just won't go down unless she is really tired.
i'm finding as she gets older she can handle more stimulation and also the sleep window seems to be bigger too. if you think he's too stimulated you could do a longer winddown...i douobt a walk in the stroller would be too much.
if he's waking after just half an hour that suggests OT to me and maybe put him down earlier. post your routine as nicole suggested and we'll take a look.