Mr. Bainbridge,
I also agree that further discussion is likely to be fruitless (as if there won't ever be a Catholic vs Protestant discussion on FR again, yeah right)
But here's the way I see it:
1 Cor 12 says there is one body. Jesus Christ is the head of that body. I believe we agree on that.
Christ is preached in your church. I am certain of that. Christ is preached in my church. You can be certain of that. We should be thankful that the name of Christ is preached in both places. (Phil 1:18 What then? Only that in every way, whether in pretense or in truth, Christ is proclaimed; and in that I rejoice.)
IMHO, that is the bottom line.