I wouldn't use unleaded, it'll run but isn't recommended with a performance engine. Doesn't do the Pistons any good.
When I picked my Cupra up I asked this question (mine has 98/95 on the filler cap).
I was told if I can use super then great but if not just use normal unleaded. They were also quick to point out that all their staff run normal unleaded (or at least at this particular Seat).
That being said, I use V Power.
regarding emergency use - I keep a large Twix in the glovebox for just such situations.....