Coming back to the point about aerial photography:
This appears to be a grey area because:
1)strict interpretation of the law means that you would need a CPL or ATPL to make a flight for the purpose of aerial photography, which classifies as 'Aerial Work' and does not fall within the exemptions (glider towing and dropping parachutists@);BUT
2) if you make the flight for pleasure purposes, happen to take a few photographs and then sell them - ex post facto (after the fact), it all becomes much harder to prove a breach of the PPL licence. The difficulty is you could probably only get away with it once or twice. Once a pattern of behaviour is established, flight - involving low flight and circling over areas photographed, followed by sale of photographs taken, the CAA would probably ask a court to consider that flights are, in reality, knowingly and deliberately being carried out for the purposes of Aerial Work. "Take him down!"
It's not worth risking your licence. Secondly, unless you're going to take a good photographer to take the pics, you will find aerial photography more difficult than you might think. I have found taking a pic with a digi camera and flying the plane responsibly at the same time is really tricky, and that's without trying to focus on any specific point on the ground.
HH