Older TVs had "HD" labels (Full HD or HD Ready, depending on the screen resolution), but they could only use HD signal from external sources, like Blu-Ray player or satellite receiver.
As far as I'm aware, it's a pretty recent model, so maybe it has an integrated HD tuner? Although I think in the UK some HD channels are broadcast through cable/satellite services. I have no idea how this works in Poland.
But Harry bought his stepdaughter a TV and he seems to think it will work ( once plug has been changed ).
Even if it doesn't receive Polish TV (which is quite unlikely), you can always plug an external TV receiver by HDMI. The price of such one is about 120 PLN.
OK, I'll try to explain all this to them, thanks for help.