And it's now all hooked up:
I opened up the mounting holes on the pedal box with my step drill, so it was just an unbolt and remove the old servo and bolt in the new one. The long clevis works a treat.
I will need longer fluid feed lines, if this all works out, as I unbolted the reservoir and it's just resting up against the bulkhead.
The elbow / one way valve on the servo needed to be removed, so my vac hose and elbow could be connected. Unfortunately, in removing the provided elbow it came apart - so I need to replace that for you, Mike.
I've tested for leaks, spraying the vac entry and the adaptor plate / servo / cylinder interfaces with brake cleaner, and no issues there.
Now all I need to do is try it out on the road.