Julia, I really feel for you and your family, and of course Floyd
It is such a shame you have had such a bad experience with your first dog and springer. Many behavioural problems can be attributed to medical conditions, though your behaviourist would probably have advised you go through all the necessary -*test*-('")s - bloods etc to rule that out as it is common and fixable.
Springers are a really great breed that respond well to consistent, kind, postive training. I'm not sure what advice you had from your behaviourist on how to deal with Floyd, but generally a 'dominance aggression' diagnosis would include stuff about you being 'pack leader' and 'dominanting' the dog - if this was the case it really wouldn't be needed with another new dog as building a close relationship based on repsect and trust would be important for you any any new dog you took on.
I wish you well in your search Julia, there are a lot of dogs requiring homes through many rescues on this forum, and pups do occasionally come up, although I feel that it would be important to match the right temperament of dog with yourself and your family after the heartache you must be suffering over Floyd.
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