Some one wherever you are can change a tyre on a wheel,never found anyone yet that could "Knit" a wheel. So,half a loaf is better than none,get that spare tyre BOUGHT !
I am lead to believe that you must carry a spare wheel in Spain by law,so with just the tyre....... it is just an infringement ? LOL
PS. If the rim is a bit... Curly ?after the puncture. You would be surprised how much a bit of heat and a 2lb hammer can make a buckled rim take a tyre back on