I'd hope and expect that it is illegal to advertise for a specific gender or nationality
Depends on context. Someone to help women in and out of their dresses and pin to adjust them could quite reasonably be expected to be another woman......well,thats what they told me when I applied for the Bra fitter job in Top Shop the other year.....
As to the "Polish",all he has to do is add the words "Polish language speaker prefered" and he's well within the law,its a "skill" not a "ethnic" thing that way :)