Hi
I don't know if this will help with your cocker but with my Millie she needs a quiet cast out when i let her of to hunt. I have her walking to heel and when i want her to hunt i have to catch her attention by bending down and saying there (quietly)as i point into an close area of cover, she then begins to hunt. She yelps if i give her to much encouragement.
We stay in NZ now and i entered my first field trial this year. I was realy worried about how my dogs would do, but everyone else was in the same boat. Even the best dogs can muck up.
First day Millie got a third in the novice, two days later she was put out for squeaking. which was my fault. i encouraged her to push into some cover, she got frustrated at not being able to get to the rabbit and started squeaking.
There were many dogs over the week, some field trial champions put out for the same thing, so don't worry many people have the same problem.
Good luck, have a go, its a lot of fun watching them.