Certainly been a few over in the last few days, see another one just whistling over, lights showing up nicely against the frosty sky.
Recall the old days when C-141s and the odd C-5 trundled eastwards from Strumble or Lands End towards Dover... I recall spotting six one day, trusty airband getting me the serials (I was recently told that if a substitute airframe flew the mission, they still used the serial submitted on the flightplan...)