I got hold a SA80 Hi F key, now this is very different to the MKVI key, the rod's shorter, pad cup is smaller and key levers are different sizes. Anyway although the cup is smaller it still covers the tone hole. I don't know what solder Selmer use these days but I could not the key and levers, so I had to drill through the key rod the remove the parts I needed. I then found a rod from an old Bundy alto, cut it to size and soldered the parts on to it. I then drilled holes for the pivot screws to fit, and now I have a working key. Now I still would like to get the original key, but at least it works for now.