Just before Normandy I fitted a pair of the 'Schipperfabrik' pannier bags to the M20..generally I am very happy with them, although they would benefit from an additional inch or two on the length of the 'cross strap' that joins the two bags together as it is barely long enough.
However, I had cause to remove them recently and two of the press studs parted company from the leather corner pieces as they were removed. The press studs are a pretty tight fit to the 'male' part of the stud fitted to the carrier frames.
Foolishly, when I fitted them I did not grease the two halves of the press studs before fitting. Probably due to this and a little corrosion the force required to seperate them caused the damage.
So apply some grease before fitting if you are using these bags....Ian
I had mine pull through the leather, yes, I pulled too hard, I tend to be that way. Now I part them by using a fine blade screw driver, a very slight twist and they unsnap easily. They are tight!