Well, with all the nice little agreements going on between EXT adn Flybe (hence why no EZY there) if the airport is sold to BRS then the flybe stuff prob wont change. However, the charter side of things will prob decrease - to increase the loads at BRS. Alternativly, the little EXT-Flybe agreement might break down, they BRS-EZY affiliation might transfer to EXT, and the establishment of more charter aircraft in the south-west mite lead to EXT launching the long haul charters that BRS cant handle.
Personally though, i would prefer it were sold to a non-BRS linked company - then what disinsentive can they have for encouraging growth of EXT?