I have bought new-old-stock Sachs hubs (Duomatic) from Velo-Classic in Germany. He also has a large collection of spare parts and may have what you need to repair the hub: https://velo-classic.de/oxid2/
Thanks I've already had a look at their site and another german stockist but no luck as yet so still looking
@Nick_S started
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I have bought new-old-stock Sachs hubs (Duomatic) from Velo-Classic in Germany. He also has a large collection of spare parts and may have what you need to repair the hub:
https://velo-classic.de/oxid2/