Hi Helicraig,
There are always 2 sides to every story, I know the very incident in which you are talking about. An explanation was given by the captain on his welcome pa once everyone had boarded and an apology was also given for the delay on landing into Birmingham.
Bmibaby always charge for extra leg room front row seats, Even on low loads people are not permitted to sit there without charge. Obviously I can understand why this would be frustrating to passengers, especially to passengers who have already encountered a delay but it is important to be consistent. If this pax had been permitted to sit there on this occasion, on another occasion they may encounter different staff who would refuse and then we get into the whole, "Well I've been allowed before".
Also you have the problem with the passengers who have paid the extra leg room fee if you then move other passengers who ask to sit there for free.