Here in the US we see flight patterns like that fairly frequently, though much lower in smaller aircraft.
http://blog.enigma.io/wp-content/uploads/2015/06/Screenshot-2015-06-02-16.38.36.png
Been tracked back to FBI surveillance flights.
blog.enigma.io/track-84-aircraft … veillance/
There’s some discussion of it on this board toward the end of the thread, comparing it with the repetative linear pattern of mapping/GIS flights:
ads-b-flight-tracking-f21/now-this-is-an-interesting-flight-pattern-t36835.html
Her Majesty’s lads may be doing something similar - though in what seems to be a fairly rural location, they may be the very least testing something similar. Honestly though, given the proximity to RAF Waddington it may be perhaps simply testing a reconnaissance system over friendly soil.
According to wikipedia “The base is the RAF’s Intelligence Surveillance Target Acquisition and Reconnaissance (ISTAR) hub” and they operate AEW aircraft and an array of drones - the plane may also be flying sensors in support of some other kind of testing.