OK so my new Defender wiper arms arrived and its very interesting! They're substantially more solidly made than the Rover Mini originals. Due to the sharper angle of the tip, the blades will rest too high up the screen, but I think I'm going to fit them anyway and see what happens. I'm not sure this angle can be easily modified, not by me anyway.
They're from "BritPart". I've emailed them to suggest they tweak the Defender wiper arm design, and sell a Mini version to the many Classic Mini owners who, like me, have 1990s Minis that they're trying to keep going as daily drivers.
Do you have a pic of the rest position per chance?