Regrettably the UKBA 'help line' staff are notorious for giving incorrect information. It's nonsense that this has to be translated in China. If you want peace of mind, have it translated by a reputable translation company. As you've already been advised, if you can't find one easily, contact the Chinese embassy for guidance.
You haven't said where you are living but a simple Google search shows this company in London.
http://www.certifiedtranslationcompany.co.uk/
As long as you use a professional translation company you don't need it certified by the Chinese embassy. It was accepted for the intitial spouse visa and will be accepted for ILR.