Thanks BOD2, i'll try changing the battery when I get home and if not I'll crack open the back and see if I can see any of the problems you highlighted.  
 
Thanks again. 
 
 
[quote name='chris_b' post='197954' date='May 13 2008, 01:43 PM']Have you started slapping and tapping without realising it?[/quote] 
 
Unfortunately no! Would be ace though...