Well, there are different types. The guifinessen is what actually thins everything out. A lot of products have other stuff to help suppress cough and other things, but you only want the guifinessen.
I did guifinessen, but I didn't use cough syrup as I think that might be a little more difficult to find guifinessen only.
I don't know what all you have available over there, but you might be able to find guifinessen in its generic pill form. Also if you have mucinex - though mucinex also has different types where it's guifinessen only or with other ingredients, but if you have mucinex over there, you might have better luck finding that with guifinessen only than cough medicine.
But I would probably look more at the pill forms as you might have better luck. I can't say for sure as I don't know what all you have there, and I've never really looked much into cough medicine as I'd rather take a pill over that any day lol but I would try looking in pill form.