Thanks!
Thanks to everyone who took the trouble to reply. It was interesting to read all the different points of view. Thanks especially to vctenderness and Flightwatch for their insightful and intelligent contributions. Apologies for my GFY post at the start! I just can't see any point in posting gormless and vacuous comments (JW411) to what was a serious enquiry which might have been of benefit to some of our colleagues.
My argument all along has been that I signed a CONTRACT of severance which consisted of one year's salary, a minute pension and staff travel privileges. BA are now arguing that ST is concessional, and can be withdrawn or altered at any time. BUT, surely not when the clause formed part of a contract. BALPA have been reasonably helpful to me, but have given up on the fight, their legal department coming down on the side of BA. BA's conduct in the matter is morally reprehensible and they clearly know that a single individual could not afford to fight this battle for years in court.
Should we really have expected anything else from the World's Favourite ?