I have bought several versions of Workbench on ebay.
Both 1.3 and 2.04, and if you are lucky I think I have a original Workbench 2.04 and extras disk for the Amiga.
I will check when I get home.
(I know I have more than one set of workbench 2.04, but I'm not shure if All the Workbench disk works, but if they do, I have one you could buy!)