hie there, l am a British citizen and would like to visit China, my question is do l need a visa for two week stay

All UK citizens need a visa to en China no matter if its a shorter or longer stay. You apply at the Chinese embassy or consulate near you in the UK, or any country but you MUST get a visa before you come, you cannot get it when you arrive. You can get a single entry visa which will give you 30 days or apply for a multiple entry visa which will give you 2 lots of 30 days, so if you leave the country, i.e. to go to Hong Kong and then want to come back in, you will need a multiple entry visa.