There's also a guy on the VX forum who is offering rebuilds (Jay), and others seem to have good results with him. The VX220 uses the same rear Brembo caliper.
Not the quickest turnaround I've heard. About £90 per caliper
Nearside rear calliper.......
Re: Nearside rear calliper.......
VX220 SC
M135i
Parajet V3 Moster 185
M135i
Parajet V3 Moster 185