I'm getting just over £2000 per month after tax. Is it likely that the International schools in Poland match this or come close to it?
You are incrediby lucky with such salary and the cost of living in Bangkok is so much lower than in Poland. If I had such salary I would stay there forever. I have never heard of such salaries in Poland and free school for your child, wow. When I checked salaries at schools in Bangkok they were usually 500$ per month and no insurance, no ticket, no accomodation. I think you will have easier and better life if you continue with your work there.