Flew alot with BA over the last couple of years mainly manchester to gatwick or manchester to zurich, With BA it depends on who's sat behind the desk on the day. Sometimes nice sometimes not - one week they let us grab the earlier friday shuttle ie 3pm instead of 5pm better for them as the 5pm is nearly allways full and they could more than likely sell the spare seats at a bigger price.
Next week allowed to do the same however blokey took the business lounge of the tickets
Week later told to forget it even tho the 3pm only had about 30 people on it.
Couldn't complain to work about loosing the business lounge as was supposed to be in the classroom until 4pm.
OH and if you get the nice cheap BA tickets of t'internet at the cheapest price - forget it they won't budge a millimetre on those ones.
Cheers
Jon