I believe Southampton did have flights in Summer 2012 but unsure if they are returning in 2013.
Vueling will not be returning to Southampton in 2013; Flybe have since taken up the route.
Any chance of a BFS-MAD route if they are expanding in the UK?
In my own view this will not happen. They are concentrating expansion from Barcelona at the moment with expansion also taking place at Bilbao, Florence and Malaga.