[Closed] GoPro 2 is randomly stopping itself recording?

Anyone else had this issue? Bought it 2nd hand the other week and haven't really had much time to mess around with it. The first few times I used it, there were been no problems. Did a few quick helmet cam vids of a minute or so, and a 2 hour time lapse. However tried to use it today and it doesn't seem to want to do videos of longer than around 25-30 seconds. I haven't changed any settings or anything like that. I believe it has the latest firmware as it has the protune option in the settings.

Just tried a complete format of the SD card (which is a 16gb class 4 sandisk) but the problem still persists. Do I need a higher class SD card?