I make the trip Italy - UK at least once a year. One time only I had a blow out on my return to Italy just after getting onto the M6 at 4 in the morning. Without the space saver I would have needed to wait the rescue. Only time I've ever had a blow out In my life but scary.
So if you don't have a space saver make sure you have recovery insurance or it will get very expensive if you have a problem.
Forgot to mention the downside of the space saver.
What do you do with the full size wheel when you use the space saver and you already have a full boot ?
Luckily ( I think ) I was traveling alone so managed to fit the full size wheel behind the passenger seat. If I had a passenger it would have been a great journey with roof down in the rain at 4 in the morning...
Maybe the tyre sealant (slow puncture) and rescue service (for blow out) Is not such a bad option.
A translator is also useful if you don't speak the lingo. It's worth downloading an app.