Speedo drives

Does anyone happen to know of an alternative speedo drive box for the front wheel that will fit the Paso and give something within about 25% accuracy?

Glad I didn’t hold my breathe on this one.
There is a piece in the “Interchangeablity List” which infers that an Aprillia RS250 one is a direct replacement.
The spindle is a different size, so the hole in the middle is too large. The tang needs cutting down, though that’s no problem, but it reads about 50% too fast. Great for the ego but useless when speed cameras are working.
If anyone knows of any alternative, I’d be interested to know.