Well we came back last week and ours is a not what to do but worked out fine.
DD aged 5 didn't sleep at all on the flight back. She slept in the car all the way home and then in bed until 6.30pm.
She was zonked out no waking her.
I thought we would be up all night with her but she went to bed when we did, slept all night and got up with us at normal time on the sunday.
Has been ok since - back in her normal routine.
I think she was so exhausted from the trip that she was able to sleep so much whereas usual best advice is to sleep on plane and have a small nap or no nap on landing day and hold out for uk bedtime.