Seriously overweight 10 year old

My daughter is 10 and very very over weight. Her and I share clothes. We are an active family. My daughter does swimming and netball twice per week. We get out and about daily in summer but winter we do tend to hibernate a little . But instead we play the Wii fit. I have two children, a year apart in age. My eldest is quite lean and no issues with weight. There is just the 3 of us. I’m self employed so when they’re at home so am I. I never and I mean never have soft drinks, sweets, chips, biscuits or anything that I’d consider sugary ect in the house for the pure reason. If It’s not there, it can’t be eaten .. She does visit her dad every second weekend and I know there are no food boundaries there. But it’s only 2 days a fortnight. I’ve seen 3 different crappy GP’s that say limit food, limit sugar.. I am! We’ve done the government program Go for fun. It was great, but not mind blowing. Still highly recommended. GP’s have no idea. I want specialists or people who actually can help . Does anyone know where you can get real actual help for child hood obesity. I’ve called the children’s Hospital. Every clinic they had is now closed. I’m Desperate good or bad please suggest. Yes I had her thyroid checked a couple of years ago. The only recent health issues I haven’t checked out is that she doubles over in pain after milk and yoghurt . Thanks mummy’s