need 3 little boys and 3 little girls from British to do voice over for a children's book

we have a series of chilren's English book, we need to find 3 little boys and 3 little girls from British to do voice over. Age is 4-10. They can record at home or a pro studio, just to make sure there is no noticeable noise. the rate is $15-20 per minute of audio. This project is about 20-25 minutes in total.
I hope to find a local child voice over team to work with on a long-term basis because we mainly do children's book projects in China. Send your children's samples when you propose. Those who dont' have a child's voice sample please dont propose