School shoe shopping blues

My boy starts high school next week and will turn 12 the following week. So far, he's had very slow growing feet, we'd often get at least 18 months out of his school shoes before he needed to go up a size.
Over these 6 weeks of school holidays, he hasn't been able to eat enough food, always hungry. It's true he has grown in height but it would appear he's mainly grown in shoe size, up 2 sizes since we bought his last pair back in July.