Think yourself lucky, when my mother died last year and I needed to get back the flights were priced at 500€ for one way.

Barcelona flights to London are also rising steeply. Spain has increased landing charges and I imagine the airlines prefer to fly fewer planes but with higher occupancy. Fewer seats means higher prices. Also Iberia is struggling and Spanair has gone bust; low cost airlines will cease to be low cost if there is no competition.

If you can get across the border, France has very competitive TGV prices to Paris from where you can pick up the eurostar. Flying via Dublin might also be an option.