Unfortunately, the one in question which my Argentine colleague wishes to open and close his book with on the air ops of 21st May (as it was the first mission of the day) is not in Kew.
Not wishing to teach you to suck eggs, but did you check for the 20th (see note 1 below)
These are the pertinent extracts from the log book entry from the photo as per the reference above
May 20th (see note 1)
XV232
Flt Lt Gillespie (see note 2)
6.50 day (or poss 5.50, hard to tell from the quality of the photo and handwriting)
13.00 night
Note 1
Flight would have taken off on 20th and landed on 21st. For various, obvious and not so obvious reasons, this would seem to be the sortie in question.
Note 2 From what can gather from the book and other posters, the crew members in question would be
Dave Ford Air Electronics Officer and Crew Captain (I think he was a Flt Lt at the time, sort of 85% sure)
Flt Lt Gillespie, Pilot, P1 (would have been Air to Air Refueling qualified, don't recall his first name??)
Wg Cdr Dave Emmerson (the Sqn Cdr, who was a navigator) in attendance. Whether or not he actually did a shift as the routine or tactical navigator, you would have to ask someone who was there.
20 hours, all but, phew that's a lot of dairy cream sponge.
PS Dave Emmerson is a lovely chap...I wonder if he ever gave anyone a bollicking? I'd love to hear of it if he did. Dave Ford is a top guy too...He gave me plenty of bollickings.