Yup, I/we pretty much know the "official rules", but, as I effectively said, "it all depends" on who is responsible for enforcing them, and the extent to which they actually do!
The numbers & sizes of dishes on the buildings & walls and in gardens (large one in a back garden a couple of doors down was there before the Gibby went up) around here before I put up my bigger dishes made me reasonably sure I'd be unlikely to run into trouble, especially as most of them are backed against next door's high fence and "greenery". Camo-netted the tall ones nevertheless and nothing was ever said by anyone.
OTOH, wouldn't have wanted to go any larger/higher as some of the neighbours might then have complained and the council might then have actually taken action.