€ Euros. You can easily exchange pounds for euros at a wide range of locations, and take cash out of ATMS for a small charge.
Spanish, though Catalan is spoken in Barcelona and the surrounding region. Some English is spoken, particularly in tourist areas, but is not as prevalent as in a lot of other countries.
+34 for Spain. Major city codes are Madrid 91, Barcelona 93, Seville 95, and mobile numbers start with (0)6.
Valid UK Passport.