I've lost count on the WCML in First.
Notable mentions:
Daniel Craig with his mum. Sat in front of me. I kept thinking, 'I'm sure it's him' - didn't want to ask, he kept whispering, then he spoke - Then I knew it was him. Again, left him alone. Acknowledge him at the end of the journey, he did too.
Iain Cuthbertson (actor) - Another 'Is it him?' moment. He had stacks of Sunday newspapers on his table. A member of onboard staff spoke to him, and he confirmed it was him. I wish I did speak to him, I just respect their privacy because they must be bothered all the time.