I think Alan may have tweeked the image to get the clarity of the gunner, not that theres anything wrong with that at all. One way rich is to get a polarising filter, if you're camera can take one. This fits on the end of the lens and at certain angles cut through glare to give a similar effect to that shown in Alans pic, but over the whole glazed area. They can also help to give that 'holiday brochure' deep blue sky.