I realize it's early days yet for The Cwtch... here are a few free-flow ideas from a business owner in a tourist town, halfway across the globe.

Off-season is a good time to ramp the social media presence; these days a lot of people use their smartphones to figure out where to go when they are on holiday.

"Claim" the business on Yelp.
I already see a few reviews on TripAdvisor; that's good.
I see a Facebook page; that's good! Get a matching twitter and auto-populate the twitter with the Facebook posts.
Claim the business with Google Business/Google maps; make sure The Cwtch controls what's ON the Google listing... it's free.
Develop your unique "gimmick:" could be anything... "Mallorca's ONLY bar without a vovel!"
You can program your credit card machine to include verbiage like "Enjoyed your evening with us? Why not give us a review on TripAdvisor!" Or "Follow us on Facebook!"
Make it easy for people; add the QC code directly on the sales slip.
Try to go after the local ex-pat clients during the winter; develop it as a local watering hole. Frequent the ex-pat forums on the web; I'm sure there's one or more for Mallorca... people like to frequent places where they "know people."
Way back in the when when I lived in Spain, there was a local bar owned by an English lady... she managed to turn part of the bar into an English-language book exchange/library. That alone was good for 20+ drinks a day.

Of course, I know it's not your bar... just thinking out loud.