I think I have posted on the wrong thread as I noticed your write up on your other 'Flash' post. I am sorry to hear that poor Flash was attacked and you have to muzzle him, it is a difficult thing to do, particularly when he is so lovely around people.
Don't worry about the fact that he isn't a rescue dog, none of my two are rescue dogs either......one day I would like a rescue dog but I have my hands full at the moment with the two girls!