PTS Meeting: Who is the Head of the Church?

In preparation for the above meeting I've been having a fresh look at the Theological Declaration of Barmen that set out the Confessing German Evangelical Church's opposition to the Nazification of the Church in the 1930's. Recent government attempts to impose its secular values on the Church in the UK have given the Barmen Declaration added relevance for our situation. The Declaration was drafted by Swiss theologian Karl Barth who was a professor at Bonn University at the time. He was later thrown out of Germany for refusing to swear an oath of allegiance to Hitler. You don't have to be a card carrying Barthian (and in case you are worrying - I'm not) to applaud the Declaration's ringling affirmation of the Lordship of Christ and the independence of the Church from unwarranted state interference. 

8.11 Jesus Christ, as he is attested for us in Holy Scripture, is the one Word of God which we have to hear and which we have to trust and obey in life and in death.

8.12 We reject the false doctrine, as though the church could and would have to acknowledge as a source of its proclamation, apart from and besides this one Word of God, still other events and powers, figures and truths, as God's revelation.

8.17 The Christian Church is the congregation of the brethren in which Jesus Christ acts presently as the Lord in Word and sacrament through the Holy Spirit. As the Church of pardoned sinners, it has to testify in the midst of a sinful world, with its faith as with its obedience, with its message as with its order, that it is solely his property, and that it lives and wants to live solely from his comfort and from his direction in the expectation of his appearance.

8.18 We reject the false doctrine, as though the Church were permitted to abandon the form of its message and order to its own pleasure or to changes in prevailing ideological and political convictions.