My daughter was on her first solo long haul flight LHR - SYD leaving LHR last night. (Well, to be accurate she went ex-DUB, but for the purposes of this thread it's the long haul part I'm talking about!)
She's 22 so not a child, but she was quite nervous, and she was flying in J for the first time, and was a bit anxious about doing the 'wrong thing'.

Anyway, I heard from her a short while ago and she said the flight was great, with lovely cabin crew. They went to some lengths to put her at her ease and said they knew that it was her first time in CW so explained everything.
Then on the SIN - SYD leg, she chatted to the new cabin crew and mentioned that it was her birthday and they made a big fuss drew her a card and gave her a wash bag from F as a gift, and topped up her wine rather more frequently than she expected!

I'll encourage her to submit some well dones on her return, but I think BA have a fan (and she was impressed with CW too!)