I have found that they have got a little better the last couple of months. When your order arrives, it comes with an English form as well as the countless German paperwork, so you do know what is on back order or not. There have been many occasions where I have ordered from them, only to be missing some items and not able to understand the German for, thus have re ordered, and eventually ended up with double or triple orders of the same item. Impatience on my part? Perhaps.
Do definitely recommend Gerstl though, definitely the cheapest stockist with English translation. Though I'm sure there are cheaper in Poland, but not as accessible for people like me.