When at Syerston on a Cadet Gliding Scholarship i can tell you that both types were seen at the airfield
Jags x2 (airframe only) - They are there as part of IOT exercise decisive edge 1/2 (not sure which one)
Harrier x1 ("Jedi 15A") - The only flying asset of the week acting as a Rouge red force buzzing the field at certain undisclosed times of the day. Just makes it that tad more real
, well....... i certainly liked it
)
(They came in the afternoon via holbeach ranges)
Hope this helps