child born in china

Dubz90, you should register your kid's birth at your embassy in China and then apply him a British passport. Then you need to bring his passport, birth certificate, your passport, your wife's ID card, your birth certificate (if required) to local entry and exit management bureau to apply a visa for him. Then you won't have a problem when taking him back to UK.

To register his birth, you should find a qualified translation company to translate your kids' birth certificate into English.