I forgot to thank you for uploading those drawings of the different pedal boxes.
AFAIK the master cylinders were produced by Girling but I have no Girling part number.
If any of you guys know where I can source one of those Maserati clutch pedal's I'd like to know as I've e-mailed a whole bunch of classic Maserati parts dealers all to no avail.
If I cannot find something that fits then I'll probably invest in a complete new AP Racing pedal box.
My LHD auto pedal box;
As you can see this pedal box is designed for auto or manual and has the blanking grommet/bung where the hydraulic clutch master cylinder goes.