I too have a stroppy cocker, but Molly started being stroppy from a younger age and now she's nearly four, she seems to be calmer. I know how stressful it can be, people don't understand when you tell them not to fuss her and to ignore her. When the groomer comes to the house to see her, she can't understand what all the fuss is about, as Molly stands still on the table for an hour with no problems and groomer says "shes a lovely natured dog". I have been told Molly has fear aggression, as usually problems occur when strangers come into the house, she hides in her crate or under the bed settee. A lot of members of the family have been nipped by her - especially men.
When she was younger, I was worried about rage as people did say, what do you expect shes a golden cocker and solids are the worst in temperament. Now I tend to think, yes rage does exist but surely not just in cockers, and I feel they get a raw deal. Just remember not all people like all people, so we can't expect all dogs to get on with other dogs/people.
My dog is also very growly, she rolls over on her back, legs in the air in submissive position and I tickle her tum, but at the same time she's growling at me, I carry on tickling her, talking to her nicely but still she growls, not bearing teeth or snapping but she has to growl/groan. I just think we should change her name to Grumpy Bum !
I would never be without her though, we all love her and know when to give her, her own space - she does seem to be a loner. We know that if we didn't have Molly, nobody else would want her.
Best Wishes
Molly's Mum