It doesn't matter.
Any fuel marked as Super had to be at least 97RON and of a set quality, to get the BS mark. As long as it had that, it's fine. Other than that it's just important to get fresh fuel: Stale 99 is worse than fresh 97, for instance.
Believe all the marketing nonsense if you like, but you'd be just as wise to buy the freshest, cheapest super petrol you can. I do.