What is the best Visa for me.

I (British) and my wife (Chinese) have been married and living in the UK for 10 years. Each year we visit her Chinese family. A few years ago we bought a 5 bedroom apartment and have savings in the Bank of China. Now I am 60 we want move to china, but my wife has just changed her nationatilty and has a British passport. But she still has a son and father in China. I have been offered a teaching job in china. (I am studing for a TEFL certificate). I am at a loss to understand what will be the best visa to apply for.