Ordering from Italy requires a bit of planning indeed. Edwin Ericsson, who lives in Buck Lake (Alberta), does it regularly. You could visit him but right now he is in Sweden (where he has family and friends).Yes, the slider is missing.
I have also found that not all sliders are created equal - none of the other sliders I have worked in this instance. So I needed to get creative. Waiting for shipping to this neck of the woods isn’t always ideal when most accordion parts are coming from the other side of the planet so often I must be thinking outside of the box’s box.
I should also point out that for a really high end instrument I would not be doing this as a permanent solution.