Nop, Profilab has a big store on Dzika and the one near Hala Mirowska is still existing, but is not as big as it was before. More complicated stuff (including cold proces or non-machine prints) is settled on Dzika. But for cold process, maybe the better way is do it by yourself?
Answering the question not asked: It's not true, water in Vistula is not capable to develop a BW film.