So I'm in BCN right now and the world here is interesting..
No RLDs but prostitution is legal. Based on my research and some very limited experience you have:
- Street Walkers (numerous areas but Las Ramblas) as you said
- Brothels / Prives - similar to the Amsterdam type of private houses, usually occupies an office or apartment floor, have their own websites, International Sex Guide pointed me to: Apricots, Felinas, La Vie En Rose, La Suite, La Prive amongst others. Can walk in and see a lineup or make appointments
- Independents - check out sexomercado with google translate or Slumi. The former has a map that is somewhat inaccurate but all encompassing
http://www.sexomercadobcn.com/app.html- Clubs - No idea but ISG reviewers seem to suggest many of the "strip clubs" function like the AMS sex clubs, expensive drinks and very expensive private time.. But apparently the girls are very hot
Of all of the above, I only visited one girl at Le Prive at their location, I saw the ad, made a call, they texted me the address and I showed up. The lineup was only 2 girls and I saw one who spoke basically no English but was very a very sweet GND look. Good luck!