Terry, if your love affair with the Clarkson is not over then I had a look at the drawings more closely last night and of the 24 castings I would say 10 are no more than round bits of metal and of the remaining 14 only 4 have some complexity about them the others being quite simple parts that you have shown you are more than capable of making with the Charlsworth.
Cylinder.Could be cut from solid cast iron or built up from bronze/steel only needing two parts and it would allow you to make it a bit longer to give the piston some clearance at the ends which it does not have on the drawing
Trunk GuideJust a turning job from steel with two blocks added to the sides to fix the legs to and some milling
Box Bedat that size I would weld up the four sides from flat steel bar and slightly angle to represent casting draft then weld on a top from plate. Thick plate could have the mounting pads milled around or you could build up thinner plate by adding separate pads.
Legs4 bits of steel, fabricate with bottom plate and plate that mates to trunck guide over thickness so they can be machined after fabrication, web is a cut and file to template as is the inner flange which also wants a bit of bending.
You could even paint it green if your heart is not set on grey with red pinstriping
Might even have a go myself, but need to finish off drawing