In my experience it really depends on the judge. Yesterday at a local companion show, there were a couple of workers in the pedigree classes and also a little show type that made Heidi look well off for coat. I don't think the worker got placed in any of the classes, though a lot of nice dogs didn't get placed in some big classes, but the little Black and white did. I know others don't bother to enter the Pedigree classes because they are workers
My Louie is 1/4 worker, clipped and castrated but he's still won Pedigree Sporting classes on more than one occasion (beating a nice cocker shortlisted at Crufts that year - sorry Bev
) Not all judges take the "Pedigree" bit that seriously and go more for "eye of the beholder" approach rather than conforming to an absolute
show type standard.
I tend to take the view of if I'm going, it's generally another £1 for the class, and usually it's for charity. Sometimes I'm lucky, sometimes I'm not