Again thanks for the advice.
I checked the camera at depth (45m) at the weekend. The problem is the AE-L/AF-L lock button which has the additional effect of locking the focus so every picture below 15-20m is out of focus! I'm thinking of removing the little plastic cap from the end of the pushing rod to give myself a little more clearance which should sort things out.
No, the eyecup is present. I used to take it off on the D70s I had but it makes no difference so I leave it on now. I just looked at the camera and the eyecup is further in than the LCD protector
The LCD protector seems exactly the same as the one on the D300 (I had one of them up until I flooded it in July hence all the new kit courtesy of the nice insurance man). I might try taking the LCD protector off. Not sure it will help in this situation as if anything it'll be pushing the camera and the AE-L/AF-L lock button forwards and away from the pushing rod causing the problem.
I can't see why it would be the shutter as it's on a swivel rod rather than in and out (so water pressure wouldn't affect it) but just to be sure I checked anyway. The shutter definitely isn't being pressed by the water pressure. The housing is brand new so I'd be really disappointed if the spring was worn.
I'll report back after my next test which is probably in two weeks.
Edited by witchieblackcat, 10 September 2013 - 03:08 PM.