All sorted and back together again. The riveted posts are strong and true and whilst there is the faintest jingle of the domed ends touching the basket when de clutched and without the primary cover the noise is gone with the cover in place. Thanks for all the advice S:)
From memory the rivet heads are what provides the limit on axial movement of the outer clutch basket, when the clutch is disengaged. Pretty “crude” way of doing it eh.