Just to clarify on the subject of tea, though it has been said already, you WILL be able to buy UK style tea here, it's just that you will pay a premium for it. My personal tip for that is to buy Akbar tea, which is pretty cheap, and really let it stew!
There isn't much that you can't get in Shanghai, and the few edibles that you have to live without make the return to the UK all the sweeter! One thing I would recommend though is deoderant. There are one or two brands available here, but they are scarce.
Other than that, though, I would say come to Shanghai and live here. Don't try to bring the UK with you, if you know what I mean. Shanghai has a lot to offer everyone and if you are open to new experiences and new tastes, you will be a happy bunny

Hair are your aeriels, they pick up signals from the cosmos and transmit them directly into the brain. This is the reason bald-headed men are uptight.