Hi Russell - tried all your advice options except removing the lens assembly (not possible as far as I can tell). Have cleaned the terminals, have left the battery out for periods have bought new batteries and a new memory chip without success.
The camera was bought new in December 2010.
The camera hasn't been dropped (anyway it's the one that is supposed to be drop proof) it's never got wet ((it's the waterproof version anyway) and not been used in freezing nor really hot/humid temperatures. Nor has it been used in gritty/sandy environment (supposed to be OK for that environment as well)
So what's your recommendation please.