It actually turned up an hour later - nice banked right-hand turn over Rowstock roundabout presumably prior to a run down the Vale to Uffington Country Show. I'm guessing it had just come from a fly-past at Silverstone?
We'd been sitting on the White Horse having doubts about the low cloudbase and the general viz in the Vale and was on my way home at the time....but probably got a closer look at it in flight than I would have if we'd stayed
As we'd come from GWS Didcot having seen the lovely A1 Tornado, not a bad day, I'd say
Ripline