You can reserve tour at barcelonadaytours.com Cost is 5 Euros to sign up, and balance due day of tour is 59 Euros. Pick up will be morning of disembarkation in Barcelona at the dock. Will drop you at hotel after tour. I have also signed up with them for a Flamenco Show and dinner the night of July 27 - cost is 76 Euros. I believe the cancellation policy is full refund if cancel 72 hrs before tour. Well rated in TripAdvisor.
Hope you decide to join.