hi there - my understanding of the working cocker 'type' is that working c's tend to have broader, flatter heads rather than the domed shape of the show cocker. There is a lot of disparity about how the 'breed' came about, and if you go way back I'm sure there was 'crossing' with springers along the way. the also get confused with the 'field' spaniel (and i won't even go into that as i'm not that knowledgable!!!)
From the working cockers i have known, they have shorter coats, are more 'sporty'looking and athletic (with the energy that goes with the frame!) than their show cousins. The ears are shorter as well, although that may be a consequence of the flatter heads (i'm really NOT calling you flathead jarvis, honestly...).
there are some working cocker breeders on here that will have a better grasp than i do - needless to say, all cockers are wonderful whether show or working