Pointy:
The problem now is that it always counts 1, which I guess is something to do with sleep and millis().
Actually the problem is that the program gets stuck in the wake function until the input goes high. When I set up the interupt using the registers, as in the earlier code, this didn't happen, but I am unable to wake from sleep using that method.
So close, yet so far! 
Regards,
Les