I'm not privy to Southampton Airport's accounts but do they make a profit as a single airport?
I ask this as many UK airports in a group relied being in a group where by other airports kept them afloat. I won't mention names.
If Southampton Airport does, then it would be an attractive buy as long as on going investment was minimal, passenger traffic had scope to increase and other streams of income could be explored and acted upon. Then there's the dreaded cost reduction program that would come into things, which we all know isn't nice.