Sadly, my camera appeared to be sensitive to bright light, well, changes in it. This could be replicated using a bright source of light such a monitor, lamp or torch. The screen went blank, but the camera was still on... and got warm if left like this.
It wasn't the card though as I tried Kingston, Transcend and Sandisk cards, ranging from 32GB to 4GB and from class 10 to 4. It could also lock up with no card in.
The camera was set up with the recommended settings, and worked fine indoors or on a cloudy day. Just not in the sun.
However, as DCM says, it is probably just a small number of faulty cameras as there's no mention of issues in their feedback after selling a large number.
It has to be said though, if you have any doubts about buying from estore009, then don't be as they've been excellent.
The customer service has been second to none with friendly, helpful suggestions.
They sent a SD card to check that this wasn't the cause of the faults, and there has been no fuss at all now that I have asked to return the camera for a refund.