Lazarus cascade classic and Mark III amp's

Have the Lazarus cascade classic pre-amp and 2 Mark III mono amps.
Does anyone know where I can get the schematics for those?
Also, does anyone know about any up-grades for these equipment?
Thanks for any assistance
The Lazurus was based on the 'Last PAS' construction article published in what was back then called Audio Amateur in the late 1970s or early 1980s.

The Mark 3 (I assume Dynaco) you can find by Googling images of the schematic.