Back again! Just to follow up the 1500' rule debate. I was talking to a very experienced commercial pilot / instructor / TRE / training captain today. He told me that he had discussed this with the CAA on various occasions, and their stance was that the airspace around a congested area was not a dome as such, but went up vertically at the edge of the congested area. So if you were to land in your garden at the edge of a congested area, or even fly along the edge you would not be breaking the 1500' rule. However, put one skid OVER the area and you are.
Just one more opinion to add to the confusion.