If you are currently looking for or have recently bought a home in Poland,
I doubt you ll find an expat who is currently looking into buying a home now( cheaper to rent) but you ll find quite a few who have recently ( 2 years ago)? bought one. Since you already filmed in Krakow and Poznan, i think Lodz and Warszawa were or are quite popular for expats.
Your program sounds great, maybe you could sell it to a Polish Channel, it would be good.