Jerry,
I fail to see the rationale for GR4s going to Boscombe unless there a very specific reason for a trial (possibly weapons/sensor related);
AFAIK it could be operated under a QARL with BAES support, but there would need to be some very big cheques signed! QQ have been brutal in chopping their ex-military fleet to save money, and to rationalise their aircraft as civil-registered wherever possible.