ok I'm upto the part where I need to get the warhead on the sunken ship, I've raised the missile and have dived in to get the option to raise the cover I've used both "normal" vision and the edsu goggles and each time I just get the press the X button and it just goes on and on I've been sat pressing the X for over 5 mins and still nothing happens! am I missing something here??

No, same thing happens to me. Ridiculous I think you can get a refund... Just go back to where you bought it.