What about an Anchor Metric-to-SAE Propeller Bore Reduce Bushing?
It takes a 1 1/8 inch down to a 25mm. I'd still need to locate a 25mm prop nut. What about the ones Beneteau uses
Anchor Metric to SAE Propeller Bore Reducer Bushings
Beneteau Prop Nut
Canada Metal - Beneteau Propeller Nut Anodes