I have my reservations about it being in a Dennison case - do we know of any other UGs in either Dennison or any local UK casemakers cases? I suppose it's possible that someone's just fitted a loose caseback.
I'm also a bit cautious about Swiss Made on the dial rather than Swiss. I have this Disco Volante which is remarkably similar.
I had always taken it as a re-dial - even if it's quite a pleasing one.
I don't think I'm buying that one, either literally or metaphorically. I think we've established on other threads that a Cartier item should have some sort of secondary stamping - e.g. on the back of the lugs (and I don't mean whatever that scrawl is on this one). I think the dial has been lifted from a scrapped 18k case (like my one below).