Using this VIN checker http://www.autobaza.pl/ab/en/web/productaa0100 I found that my Holden Astra Convertible was, in fact, "assembled" in the UK! Guess it makes sense as it is right hand drive . . . but interesting all the same. Guess that explains why the build quality of my wife's G 5 door (Antwerp, Belgium made and assembled) is of a far superior quality to my G convertible.
Not meaning to have a dig at you guys, but let's face it, the UK auto industry doesn't have what one would call a good reputation for build quality.