Yes, but it was from Stradishall. Without checking my log book, we may have staged through St Mawgan one way or the other. We had lunch on the wing at Porto before arriving in Gib.
The previous time had been a Varsity when we overflew Spain. The weather was as you said so we delayed a few hours. I remember briefing the pilots on RW 27 only to be told it was 26. I corrected them saying it had just been updated with new variation.
I then waited 40 years for another opportunity. It came at Coningsby pre-Typhoon. The variation changed but they couldn't afford to change the numbers at the time.
