Main issues were with the name calling. So it would go a bit like this:
Bully: you're gay
DS: you called me that yesterday. And the day before. And the day before. Getting quite bored now.
Bully: cock sucker
DS: haven't heard that one before. Oh wait. I have. (Yawn)
Bully: you're such a dick
DS: and you're really starting to bore me now. Run out of names to call me?
It was all along these lines really. Sarcastic. The responses musn't show defensive (as in, defending what they've called you), musn't show emotion, musn't retaliate to name calling back, but just shows them up to be the dick they are.
All situations are different. Talk to your DD. Find out the main bully.
Just discussing it will help. I remember my little son's face when we walked to school. He was so happy with his little stock replies he'd practiced, he gave me a big hug and said 'thanks mum' because he'd been given the green light to be rude I guess.
But again, this might not work with a child too afraid or it's more serious physical bullying.
Good luck x