What suprises me, and I admit to beingan outsider to the area, is why the BAA don't use their extensive clout, and persuade both Ford and the Post Office that they could relocate elsewhere in the near vicinity.
The reallity is that the future of any Ford plant, is only viable from year to year, and anyone who thinks they are a permanant fixture should only look at Vauxhall at Luton.
The Post Office are equally unstable, and could either move or close their Southampton operation with no further thought.
Yes it would cost them money, but it's nothing that the BAA haven't done before elsewhere, and the ultimate gain would see Southampton having increased space, which hopefully would accomodate both a runway extension and increased parking area on the airport itself.
I accept that at any BAA airport, commercial activities are always going to overide G/A, but if the above proposals were feasable, perhaps everyone could be accomodated.