B:SM car parks offers one solution called "P-8 dias" where you can leave your car in a secure car park for up to 8 days for only 45 euros. They have a custom built car park that is in the Forum area of Barcelona where this service operates. You can also leave your car there for longer periods however you will need to arrange this with the security office at the car park when you arrive.
You can buy the P-8 dias card from the car park itself. They are open 24 hours / day seven days per week. You can only use the P-8 at the Plaça del Fòrum car park.
Hello….I don’t know the exact answer to your question but you might try ringing or e-mailing the following in Barcelona:
Tourist Information Telephone: +34 93 285 3834
Tourist Information E-mail address: email@example.com firstname.lastname@example.org or looking at this web-site www.barcelonaturisme.com
Hope this is useful……. Heather