Teachers like you are not only language teachers but also cultural mediators of the language you teach.

Absolutely right. I would always teach things about british culture and british food through ppts and other examples. It is not just language you are teaching, but that of a different culture. And given that many chinese students will go on to study in the UK, getting a cultural background from a UK native english speaker is invaluable I would say.Just as learning mandarin from a native speaking resident of China would be a big plus to any UK businessman or prospective FT going to China.