Being a member of the club, I have paid a bit of attention to the subject. I have never seen
Sweet n Low in Spain. They do however, have plenty of non-nutritive sweeteners.
The tablets are usually a blend of Nutrasweet and cyclamates, the sweetener that was banned in the US years ago.
I carry a supply of my own because sometimes it is easier than asking twice. Also, the tablets are hard to sprinkle on fruit or yogurt.