The Defence-wide formation flypast limits are available for all to read in their miserableness: 500ft minimum height and 20 degrees angle of bank. Google RA2335. Any lower or steeper (or indeed a second pass according to some lower-level orders) and it becomes a role demonstration, which for performance in public needs PDA just like a display! It seems that straightforward kinds of activity that any military aircrew could deliver safely and professionally with barely a scrap of paperwork have been caught up in the post-Shoreham clampdown. A sad legacy indeed.