Right, this is all sorted now, the seller sent me over the details on how to reset the switch - its very simple to do, basically remove the and then loosen the cover to allow the slider to move freely to the correct position then retighen. It seems that I am missing a screw on the plate which is why it might have come slightly loose in transit and slipped, its all sorted now! Im glad its quite a simple camera to work on, its firing perfectly now.