The Williams 1 had the parcel shelf from the Clio Baccara (top of the range 1.4 model). It is thick carpet and grey with a suit carrier underneath.
http://www.289cobra.com/cliowil43.jpgThe Williams 2 and 3 had a thinner covered parcel shelf, the same grey colour, also with an identical suit carrier underneath.
The lesser models had the same shelf as the Williams 2 and 3 but with no suit carrier.