The TB is now in Gran Canaria, in the Canary Islands. It's not La Gomera, but it's the closest I could get!
From here, I heard a guy whistling in the Gomera style in the beach a few days ago, so this TB at least has heard it and I think it's magical.
I let the TB in a TB Hotel in a non-touristic area, to avoid any German or English geocacher to take it with them (there's a lot of "guiris", as Spaniards called these tourists).
It was a pleasure to help this TB and I really hope it get to its destination soon.