Thank you ORAC for the AW&ST quote in your #32 above. It would seem that the UK is in much the same situation as described in the piece, ie that unmanned aircraft systems may not meet domestic airworthiness requirements, but are flown in domestic airspace for training, testing, or development purposes. The solution of ingenious routeing previously mentioned does not seem viable, if only because of the ever presence of sod's law. What is acceptable in an operational area (clinging to the outside of an Apache on a rescue mission into a firefight for example) is often a no-no back home. From what has been said about the issues with Watchkeeper I would suggest that it fails to meet the most basic of airworthiness definitions (EASA):-
"Airworthiness is the measure of an aircraft's suitability for safe flight."