Advice please

My baby is almost 13 months. He usually napped 3 hours after waking and then second nap was 3-3.5 hours after that. Only now as he’s getting older he’s not tired after this amount of time. He usually napped around 10 and then around 2 pm which worked out well for picking my eldest child up at 3.10pm. Only now with him not being tired after this amount of time he’s refusing his usual naps. I don’t think he’s ready to be transitioned to 1 nap just yet but I know if he naps after the shchool run his bedtime will be really late. Im just looking for some advice on what other mums do in this situation?😊