Ribena is a cordial, and I have seen lime juice here bit not the regular.
No sparkle.
So I grew up with this, well before Coke was common. I remember the milkman delivered fizzy pop, Corona? with the milk but it was limited, once a week or special occasions.
So a cordial you added to water, i never measured it but say 10 to 1?, perhaps as the strength varied. You just know how much to have according to your taste.