Oh, you might be suprised. English TV and Movies that have become popular over here have made some purely British insults more familiar to us, even if we prefer our own.
That being said, give it a rest. I find the word "Mick" to be offensive, and despite knowing that "taking the Mick" refers to Mickey Bliss and not a derogotory insult towards Irish, doesn't mean that I don't/wouldn't feel uncomfortable hearing that phrase if I'm not expecting it- simply because I'm
not familiar with it.
Just because I find something distasteful/insulting doesn't mean I'm ignorant for feeling that way. It just means I'm coming from a very different view point than you are.