MezzoLew, that's a nice bike and very good price. I think that is one of the later models, the seat clamp is the updated version and as far as I can tell from the photo, the fork end clamp design is the later one too but I could be wrong.
I believe the Bike Friday was in existence well before the Mezzo but design concept of a rear swinging triangle and rigid main frame tube is nothing new and appears on other folding bikes, Birdy being one of the most well known.
Thanks for your comments - nice to know I have a newer version with no "bugs" or "surprises"
I will take some more close up photos when I am back on my bike - I have stored it in my B&B close to where I work so I can get out in the evenings but am holiday for a couple of weeks.
The Ori C8 also seems to be a Mezzo copy.