Hi there.
We had a really mouthy one.
The only thing that worked was exclusion. As soon as she did it- bang-'no biting'-you're out of the room. Immediately. No talking, no nothing, just pick her up and put her out and shut the door. Leave her for 30secs. If she does it again, same, but for 1 min. Again..1 min 30.etc.
You have to be committed to doing it every single time.
If you'd rather not pick the dog up, then leave yourself, but everyone in the room has to go. Immediately.
It's a pain in the backside but it really works. Cockers love to be with their people. To be excluded is the worst. Also, if they're out when they're ramped up, they're not escalating their behaviour and doing all sorts of other naughty things as well.
I do recommend this method-it's the only thing that worked for us and our cockerdile.
Best of luck.