Files are .MOV using the h.264 codec and are about 5mb per second.
Spot on, just looked, a couple of examples
A 9 seconds long video is 50mb
A 19 seconds long video is 103mb
A 43 seconds long video is 215mb.
So, yup, average 5mb per second.
so about 25mins of video on each card. how much did it set you back? about £160+?