Has anybody else noticed a sentinal R1 flying a large rectangular pattern over different parts of the UK often for many hours at high altitude? I have noticed one (and heard it on the scanner) on a number of occasions over the central UK over the last month or two. The callsign is always 'snapshot' followed by a number eg. 'snapshot 1' - appropriate I suppose for an airborne surveillance aircraft! Anyway, please get in touch if you have any further information to add about these flights. Thanks, Mark.
