[Eotz]

There is also a direct flight to Bilbao with Easyjet from Stansted. From Gatwich and Bristol, Easyjet also flight to Biarritz that is at about 1 hour and half from Bilbao. Santander is at a little bit more than 1 hour.
To Biarritz also fly ryanair but from Dublin, Birmingham, Stansted and Luton.

There is another option direct to Bilbao but much more expensive, with Iberia/British airways from Eathrow.

Hope this helps.

Regards.