Welcome to the Aprilia family indeed! Is it a Gen 1 or 2 you have, James?
Gen 2 !
Did have a picture but something broke so fixed it now

Welcome to the Aprilia family indeed! Is it a Gen 1 or 2 you have, James?
It's to do with the position of the master cylinder, get some AP rearsets to relocate it and that will solve the problem for good.