Originally Posted by corporate-wage-slave

Welcome to Flyertalk and welcome to the BA forum.

In this case you are actually interested in BA2203 LGW-CUN since it was the source of the delay, and it has codes ZO and ZY on it. The operating aircraft was YMMB which was in LGW from about 11:15. So the LGW-CUN timings are consistent with BA wanting another aircraft for that service but ended up using YMMB instead. In almost all cases, what the pilot says is what actually happened, so that information you obtained should be considered the best and most reliable source, hence I often stress the importance of doing what you did - listen to the briefing. I imagine BA will just pay up for this delay, I doubt they will try to get out of that.