Interesting read TCAS FAN. Will have to find 5 minutes to soak all the technical details up! In the mean time, I'd like to just comment on...
their reluctance to purchase the freehold of land in the southwest corner of the airport, at the time that they bought the airport
As far as I know it was less a case of 'reluctance' and more a case of the land owner proactively screening that parcel of land out of the deal with BAA. Ok, so perhaps BAA didn't push hard enough to get the land included, but it could well have been a deal breaker. Better to have the airport with constraints than no airport at all.
A very astute deal on the part of Peter de Savery... perhaps to BAA's lament.