If you have problems with your Aprilia’s brakes take a deep breath and grapple for the wallet. For a ‘Priller you have to buy a £45-50 slave cylinder (not just a seal kit), which is annoying because all it needs is the bore of the cylinder cleaning up and the seal replacing, and it’ll work for another 5 years.
So now, rather than repairing a perfectly good part you have to replace it, at substantial extra cost. Bah! Thissun needed the clutch and rear brake slaves replacing.