can you enroll for IFR directly after the SEP-PPL?
Have a look at the
CAA website here.
You will see that you will need 50 hours cross country as PIC, so that is unlikely to have happened upon issue of your PPL.
how long does it take?
How long is a piece of string? You will need to do 55hours flight training and you need to do the groundschool and sit the exams.
is it possible to do it in a non-JAR country? Australia for example?
For a JAR licence you will have to do the training for with a JAR approved FTO; dunno if there are these in Oz; there are some in the US. You can also train for any ICAO IR and do the conversion when you are back here. That takes the groundschool and writtens and 15 hours flight training and the checkride.
has anybody any experience with training in Spain
Not me!
HTH
FD