Would like to find out, from those residing in Poznań, if there are any good driving schools that offer the course in English.
Absolutely - I highly recommend OSK Arkadia - oskarkadia.pl - make sure that the practical lessons are with the owner, Arek - and you won't go wrong. He is a very very passionate guy about driving, and he treats it as a science rather than as an art - I passed both theory and practical first time with him. Perhaps the best thing is that he's a very talkative guy who will explain everything well, and he is very patient. Can't say a bad word about him and his school
Perhaps the best thing I can say about him is that he is patient - if you tell him "hey, I need to practice this" - then he won't have any issues with it. Too many driving "instructors" are grumpy men, but he certainly isn't.