CAA don't want them in UK airspace.
I pointed to that in an previous thread on the Mi-17 when the DA42s appearing on the military register was discussed before this article was published, stating that the DA42 would be able to fly anywhere over the UK, whereas a UAV cannot. But that would base the assumption that these were purely for use for a bit of "recreational" flying over downtown Bradford or where ever, rather than overseas. My first assumption was yep these are for use over the UK or even for testing purposes (maybe as part of work to integrate UAVs over British airspace or something like that), but seeing as the Americans are even looking at manned ISR aircraft similar to the DA42 specifically for Afghanistan and Iraq, it becomes obvious that there has been a sudden shift back towards fairly inexpensive manned ISR air assets whereas in recent months/years there was a gradual move towards UAVs in this role.