Study / Moving to Poznan from Barcelona - school for my 2 kids [2]

Hello everyone
I have a job offer from my current company to be relocated in Poznan for 3 to 5 years. We are living in Barcelona Spain and our kids are 2 and 7 currently in public schooling. We at home speaks all english and our sons have already a good level of english watching movies, cartoon, goong into private classes on top of what the current school offers. Adaptation might be complicated but we believe that it will be ok.

Of course I need to mention that compared to other threats I have been reading, money won't be an issue as tuitions and all fees will be managed by the company.

Actually I am looking at all international/english schools (as there are no spanish or french (i am french)) and I wanted some advices on what would be the best school in town where I should consider my kids going and of course, both in the same school. We are looking at quality of education, installation, extra curricular activities (eldest swims and play sax) and of course we would like to feel as much as possible « cared » for the youngest one.

We should arrive sometime this summer for them to start school in sept.
Thanks for your help.
Cheers