Looking for effectively bilingual English-Mandarin speaker for corporate gig

Hi there, a quick one today - this is a favour for a friend. She's looking for an effectively bilingual English-Mandarin event manager for a corporate event in Beijing - the company running the event is based in London hence we're recruiting either from London or Beijing. Very good money for the right candidate - details upon application, but good grief, do you know how hard it is to find anyone who is fluent in both Mandarin & English in London? Crikey. This is a one-off contract for an event - but you can extend your stay in Beijing for a holiday and whilst you're working, everything (flights, hotel, meals etc) will be paid for.

She's trying her best to find the right talent in London and Beijing - but as a last resort, we may consider flying someone in from Singapore IF (and only if) we fail to find the right candidate in both cities. I have identified the right kind of candidate for her:

1. Either someone from China who was brought up in England, hence speaking Mandarin with the parents but educated entirely in English
2. Or someone from the West who has spent many years in China and has learnt Mandarin to a first language level. 

Either way, it is a tall order. PRCs tend to suck so bad at English and white people struggle so much with Mandarin.  LIFTers, if you do know of any effectively bilingual (Mandarin-English) candidates in London or Beijing, please send them my way via the comments section below - this is a great opportunity but I must stress, we are looking for people who are totally fluent in BOTH languages. Thanks. 

Fancy working in Beijing?