AlanM, no offence taken, whatsoever. Your comments have been very interesting - I just didn't want you to think that I missed any of the black and white stuff, it's the tricky grey area that I'm curious about.
I've looked at both the 1/4mil CAA chart and an OS map and from that, if you exclude the reservoir and the river, I don't think the average SEP can do it. I have that GetMapping photo book already actually, so I'll take a look at that.
From what you're saying it sounds like the CAA have, through not complaining about the practice, said it is acceptable, at least until someone crashes. As per my original question, I wonder if there are any other cases where the CAA has let something happen, with their knowledge, only to turn around later a prosecute? In law there is the idea that anything done regularly enough with the knowledge of both parties can override or at least extend an expired contract (can't think what this is called, I'm not a lawyer, obviously) - I wonder if that would hold up as a defence, along the lines of "You've watched us do it a thousand times, you know we do it, you said nothing at the time, therefore you've implicitly said it's okay to do it"?