I've seen the film, or at least, one that has a very similar opening scene - its about all I remember from it, other than film being crap. iirc its called "The Zero Option". There is an imdb entry for that, with a vaguely similar outline. Don't remember anything about a jewellery heist though.
Least ways, I remember it being called "The Zero Option" - a few years ago I was wondering about the film, webnt looking, couldn;t find much out about it other than it had another title - much like Euan Lloyd's Who Dares Wins was titled "The Final Option" for it's US release.
The only other thing I recall from the film is that there was a pretty well known male actor. For some reason I thought it was Craig Fairbrass (London's Burning), but imdb show's it isn't, and the none of the actors credited ring a bell.
The film was utter tosh, so much so that even a bunch of us young, impressionable squaddies binned it; and we managed to watch all sorts of crud back then (MIA, MIA2, How Sleep The Brave, etc!)