Watching the series it's fairly clear he's had his share of mat time, and unless the sections in HK were rehearsed, his cantonese is passable. It's odd he never discusses what his styles were/are, unless i missed it , but then, the point of the show is looking at other arts, not showcasing his.
He mentions a lot of arts that are not credible and a lot that are, but the thing I like about this book and him is that he never slates any art, he seems to see them as art forms rather than just hardcore fighting sports, he just puts the facts out there for us to make our minds up, I guess it's his way of getting martial arts on the telly....... (OK I admit sometimes on the BBC series he seemed like he was poking fun at some of the arts and so called 'masters') but half of them were pretty questionable right?
I'm not sure about what his linage is, who cares quite frankly: I saw the photo's of him as a kid in the chinese temple all uniformed up (TCMA is his background) and then the stuff with the Marines when he was in 20's but I couldn't care really he may not be a ninja or a mma Star but he has clearly put in a fair bit of mat work from the way he moves.
I hear he speaks fluent Chinese and was a translator before getting into TV is that true?