Pages failing to competely display
 

For nearly a week I've had pages occasionally failing to be displayed completely.
I get the top advert/ second box with main navigation and third box below it saying which folder I'm in and that's it.
The rest of the page is in grey.
There's no timeout or any boxes at the bottom waiting for anything, so I presume that page thinks its fully loaded?
There's no pattern to which directory it is.

F5 brings the page back.
It used to only happen a couple of times a day but his morning its already happened 5 times in an hour.

Nick

Thanks, ive escalated this.