Nice to see a thread that is about something positive for a change. I don't normally swing in this forum but maybe some CC out there can let us know how to go about responding positively to excellent levels of service.
I heard that BA CC can be nominated by pax for awards and used to get things like a bottle of bubbly or M&S vouchers. I've filled out dozens of the in-flight questionnaires but have never had any feedback. Is a nicely-worded letter to the CSD or Ops Desk the way to go?