At 3 yo, his nap time is quite early. I think most parents on here have said their 3yo toddler is taking a nap between 1-2pm, with about 6-7 hrs of awake/activity time before naps. My DS who is 3.5, is napping a couple times a week and it's no earlier than 1:30/2pm.
DS might be compensating for too much day sleep before bedtime. He needs about 11-12 hrs of awake/activity time.. currently he's getting 10 or less. I hope communications are going well with the school and if at the very least, give him some books to read until 12:30 or so, then clock to see when he falls asleep. It's great they'll wake them at 1:45. But with needing about 6 hrs of awake time, especially after a 2 hr nap, DS is likely undertired for bedtime at 7:30.
At the very least you can push BT to 8:00, and try to have him do as much physical activity before dinner as possible. Eventually, that early of a nap time could cause a shift in his wake up time as well as he his sleep needs drop.
What do you think?