What is the education system like in Poland?
The Mods have linked your question to an old thread from 2015 but since then educational reforms have taken place which would have a direct impact on your child if you move to Poland. Basically the present government PIS undid a number of educational reforms that had been put in place after the end of Communism and have returned the system to the old form which existed under Communism. Here's a couple of articles that will get you up to speed:
Consider very carefully what you're doing in making a decsision, as an Englishman,to raise your family in Poland. Inform yourself about what's going on in Poland regarding politics because you'd be coming to a country that is not a long established democracy and there is no guarantee that they will even remain in the EU. They've had nothing but conflict with Brussels in the last three years.
Also consider that your wife may initially agree to live in Kraków but will probably ultimately want to move close to her family and your son's grandparents. You may well end up seeing your kid once a month because it's simply not practical to go backwards and forwards every weekend. Even if you can do the weekly commute, it'll be exhausting for you and you won't be a part of your child's life on a daily basis.