I had had the following in from a member:
“To cut to the business; I have learned Nauticat now fit ROCA arms and blades which fit the 13mm shaft of the wiper motors. Price for a ROCA arm is EUR 41.30, and blades are EUR 11.30, both ex. Finnish VAT (24%). The ROCA items can be viewed at: http://www.rocaindustry.com/wipersystem/Product/Wiper-arm-Standard/268/Full%7C448/. I have ordered 3 of each and await delivery.”
Looks like this might work for those of us in the EU.