There is absolutely zero issue buying lard in Poland. Literally any store will have some in fridges next to meat.
But in Britain we do have, or once had, something distantly related:
https://en.wikipedia.org/wiki/Dripping
https://www.independent.co.uk/life-style/food-and-drink/feat...
I'm going to have to get/make some. (I suspect my wife won't be happy).
This sounds like something they could do in Ukraine. Was the large a solid piece, or a spread? Eating solid pieces of pork fat is very normal in Ukraine.
https://www.theguardian.com/world/2015/mar/06/salo-ukraine-n...
I haven't had a chance to try to Ukrainian style solid fat!
https://www.tesco.com/groceries/en-GB/products/300346570