Supportive hard soled shoes for toddler

Hello, we’re currently starting our assessment journey for our two year old son and although not the most important issue raised by our paediatrician, one of them was to get him some different shoes to help curb the constant walking on tip toes so he doesn’t develop calf issues. She mentioned a shoe that’s supportive around the ankles and stiff soled. His current boots are quite flexible on the sole. Does anyone know where the best place to find appropriate toddler shoes is? He’s always worn Clarke’s shoes so hoping to find some in our local branch but thought I’d ask to see if anyone knew of anywhere else that I could try or offer any advice in general about tip-toe walking.