Really easy to replace, I managed it without removing the fairing. Three bolts and a rebleed. I used a CNC with the standard bore. Some change it to reduce the lever pressure, but I didn't find it that bad so left it stock.
Mine started as a very notchy feel in the lever so I checked it and greased it (didn't see a leak), but it came back. When I removed it the internals all fell apart. Lots of people rate the Ducabike, but the CNC is also really good and has a different internal design to the OEM.