Is legalisation of birth certificates and marriage certificates necessary for S1 visas?

Hi there,

My wife and children have just got an S1 from the UK to accompany me to China where I am on a X1 permit. We have got the above certificates notarised but are not sure whether they need 'authenticating' by the Chinese Embassy here in the UK before we go so that when we submit everything for the 'residence permit' everything is covered.

I can't find any information about this on anything online, and as we only have a couple of weeks to go before leaving, would like to have some peace of mind.

Many thanks for any help you can give.