You can see a 'in the making' photo here:
http://www.retrokit.net/79.html
You can see the three different elements of the body and 'head'. All were built from round flat pieces of plastic card and super glue, and sculpted with knife, files and wet'n'dry. The main problem wit the head and the flat, upper part of the body is that they are actually made up of 'slices', some higher than others, rather than a smooth surface with 'simple' panel lines. The steps were created with thin strips of plastic (white strips on that pic), then the 'higher' areas filled in with Milliput (greyish areas).
The lower part of the body is built in a similar way but was more complicated because there are many deep triangular (or rather more pyramidal) recesses in the rim.
The 'arms' were the easy part of the project!