DS2 is 16 weeks and REALLY loves his sleep. I mean 12/13 hours at night with no feed, and 2 x 3 hr naps in the day in the cot, if we are at home. He was only awake for a total of 6 hours yesterday! However, he does not sleep so well out and about so when I have DS1 (at nursery 4 days, school in Sep) or we are visiting family DS2 can be very unsettled if he does not get the daytime sleep he needs. That said, a day of bad naps does not seem to disrupt his night sleep. I know I am lucky to have a baby that STTN but days are either stuck at home or managing a very grouchy, OT baby. Just looking to hear some views really.
But you could try a snooze-shade over the pram and white noise on your phone with him in the pram to block out external sound and light when you're out and about with him and he is sleeping e.g. in shops?