Hi Oliver
Cocker Spaniels, Field Spaniels and English Springer Spaniels are all entirely different breeds (although if you go back a hundred years or so, they developed from similar ancestry) If you want info on each breed, go to the Kennel Club website (
www.the-kennel-club.org.uk) and check out the Discover Dogs section (look under Gundogs). There are also 3 other Spaniels in the Gundog Group - the Sussex Spaniel, the Welsh Springer and the Irish Water Spaniel.
Working Cockers differ from the normal show/pet-type Cocker you may be used to seeing as they are bred specifically to work in the field as gundogs (the breed's original purpose). They have shorter, finer coats with shorter ears and a squarer, blockier look to the head. They can appear to be leggier than the show-type Cocker too.
HTH
Jane