Good one Frenchy, wish I had known about them.
While you have it apart. The sprockets for the '56 '57 Areil hubs are different to the later one's and a bit harder to find. A mod I have done is to machine off the teeth and fit an after market sprocket bored out to fit over the old sprocket hub and held on with six bolts like the way they do modern discs. That way I also have spares already bored in different sizes 38,40,44 teeth.
Cheers