Oh .... OK that explains it!
Must go back and check the example - I thought it checked out for what I thought was intuitive - D&F give a process for determining the matrices.
Just another question I am still struggling with ...
On page 842 of D&F - see attachement - we are told to make V into an FG-module by considering the action of a group ring element on an element of V.
However when we come to Example (3) on page 844 (see attachement) we find D&F talking about the action of Sn on V rather than FSn on V ... until we come to the specific example of 3-dimensional space where D&F resume talking about the group ring FS3
Are you able to clarify this