I would advise against doing your PPL theory exams in Poland. I did it in 2016, and while the school gave me all the resources I needed, the questions were translated from Polish with Google Translate. The questions and the available answers did not make sense and the only way to pass the exams was root memorisation. I passed the exams in one day, so it was not hard.
Hopefully, after 4 years, things have changed and the ULC improved their database. For the rest, my experience with the ULC has been very positive.