https://cimg5.ibsrv.net/gimg/pprune....efbe579301.jpg
Great fun it was too! Close? Close enough for the Sovietski crew to get a good look at Sam Fox in the Sun's Page 3 Calendar held against the flight deck window!!

I do recall one memorable incident when one of ours moved underneath a Bear to grab some HH shots up in to the opened weapons bay . At which point there was a dropping of some of its contents......... :)

That's it. The receiver needed a bit more perspective than just a big camouflaged triangle.
As for rules... I guess keeping the barrels of those tail guns up may have been one of the (unwritten?) ones.