Interesting one this... I traded in my old 07 plate Zafira 1.6 club for a brand new 53-plate 1.6 Exlusiv petrol (cheapo special offer!) and have picked up on an audible clunk sounding similar to that reported by other forum members. This clunk occurs once, and only once, when driving off and speed goes above approx 13mph, regardless of how far I have driven. It can be felt slightly through brake pedal, suggesting it might be more likely to be ABS or brake system related than any door auto-lock system (I hear or feel no clunk from the door area). Incidentally, did try the trick of trying to go into the "hidden" user menu using the indicator and washer stalk to review set-ups, but no luck: must only be certain models...
Don't really need a solution to this as such, but just thought I'd let other people with same issue know it's not just them having this "problem"! Having said that, still curious as to what's causing this!