I did some hour building with aerofan out of cuatro vientos
2 years ago and found them very friendly.
ATC spoke english if spoken to in english and the biggest school there aeromadrid encouraged their students to transmit in english so it wasnt all that bad.....after a bit of getting used to.
as most of my flying was solo im not sure about the level of instruction but a good number of instructers spoke english.
GOOD LUCK !