I just found this. I don't know whether the assitance is sufficient. What ratio do our servo's operate at?
Compact Dual Circuit Remote Brake Servo
2:1 power boost ratio @ 600mm Hg vacuum.www.carbuildersolutions.com
Bit of a thread revive but I've also been looking at these to bin the factory rhd set up. A 5.5" single servo sure would free up room in there.