Breguet Marine Chronograph 3460

Dear All,Having had all my watches stolen recently I was just given the above as a present to help re-start my collection - I chose it over the new one as I wanted a smaller / dressier chronograph than the Marine range which replaced it (or indeed a Royal Oak). Was hoping you might all be able to help me with a few things:

1) my clasp keeps opening and the watch has nearly fallen off my wrist on a number of occasions (since when it is quarantined in its box) - is this a common complain with the Breguet clasp? looking at it, it does not seem very secure and the last thing I want is for the watch to end up falling off my wrist!

2) where can I find more info on the watch / the marine chronograph range? ie what is the difference between the platinum and WG version (eg different colour dials?), when did manufacturing start, when did production cease etc. Any other interesting facts about the watch?

any help would be much appreciated and I would greatly enjoy the watch more once I know more about it!

Many thanks!