You're probably right, I'd seen the cross in the southeast and also on the pictures of grave stones of departed relatives in Wroclaw and Zelone Gore. So i assumed it was common in the whole of Poland.
I'd googled Polish triple cross/Polish cross before and come up with nothing but film reviews. Thanks I'll try lemko cross this time...
I just briefly googled it : Lemko cross - lots of info
Did that couldn't find anything other than Lemko history and a ref to a lemko cross.
there is a definite story of how the cross with the three bars came to be, someone once tried to explain it to me but the bulk of it was lost due to my poor polish.