mardave cobra diff woes

[fidspeed]

hi folks

having picked up a modified cobra from legend of the north west roger woods collection . im having diff woes

im not sure if my diff is "special" thanks to roger or a std mardave diff
im struggling to find much info or exploded drawings or manuals

I have an early diff which has no diff plates and balls run directly on diff halves my modified one has diff plates (approx. b4 size) there does not appear to be any spring or belville washers and the diff adjustment screw is locked by a grubscrew ala Schumacher

can anyone help with drawings or info any where

regards dave