FlyingJ - welcome to FT and the BA Board. An excellent first question. Personally, when the crew have gone above and beyond in a way which is not standard policy (rather than just being great in general at delivering service), I have been sure to focus on every positive aspect of the experience in detail, but not mention anything which may get them in to trouble. I think it should be possible in your case to write about the CSD's great service, welcome, attitude, etc. and how he went above and beyond your expectations and delivered a fantastic flight...without specifically mentioning your friend's upgrade.