An Argument about the Required C of E Belief

At Fulcrum I'm insisting I have the correct interpretation of the Declaration of Assent against that of a literalist Calvinist. My opponent wants to insist by the power of his argument due to the content of the Preface that Anglican ministers are:

...stating their conviction that the Articles are true because of the leading of the Holy Spirit.

 The argument focuses on both the Preface and the Declaration, so I'll reproduce these here:

PREFACE

The Church of England is part of the One, Holy, Catholic and Apostolic Church worshipping the one true God, Father, Son and Holy Spirit. It professes the faith uniquely revealed in the Holy Scriptures and set forth in the catholic creeds, which faith the Church is called upon to proclaim afresh in each generation. Led by the Holy Spirit, it has borne witness to Christian truth in its historic formularies, the Thirty-nine Articles of Religion, The Book of Common Prayer and the Ordering of Bishops, Priests and Deacons. In the declaration you are about to make will you affirm your loyalty to this inheritance of faith as your inspiration and guidance under God in bringing the grace and truth of Christ to this generation and making him known to those in your care?

Declaration of Assent

I, A B, do so affirm, and accordingly declare my belief in the faith which is revealed in the Holy Scriptures and set forth in the catholic creeds and to which the historic formularies of the Church of England bear witness; and in public prayer and administration of the sacraments, I will use only the forms of service which are authorized or allowed by Canon.

...There is a difference between 'the Church' and the individual. The preface describes the Church of England. It asks the individual to "affirm your loyalty to this inheritance of faith" and that is deliberately put in general terms. It is the individual's "inspiration and guidance" and then the actual declaration itself makes a distinction so that:

• you declare your belief in the faith. The vital part.
• revealed in the scriptures. The strongest aspect.
• described in the creeds. Where it is set out.
• the historic formularies beat witness. Some formularies that bear witness as a whole.

The one thing the Church of England cleric MUST do and that is stick to the Church of England forms of conducting services. (And it's very often the evangelicals who bust that one rule whereas the liberals stick to the rules and swallow and profess many beliefs they do not actually hold).

When I was in the C of E and before I took over the subjects of the discussion group this chap used to introduce the articles for the pure reason of showing how ridiculous they were. I used to think that this was a waste of discussion time simply because no one was required to consent and assent to them any more.

Indeed at one time the Church of England cleric had to consent and assent to the Book of Common Prayer. That is why the Puritans, some 1700 of them, left in 1662. In 1771 Latitudinarian Theophilus Lindsey organised the Feathers Tavern petition rejected twice by parliament for relief from assenting to 39 articles. He left the Church of England to set up an Arian liturgy Church in 1774 called Unitarian. I'm not well informed about the history of changes but I believe the significant change happened in 1974 to 1976.
The brief self-description of the Church of England on its website points out that there are three traditions of the Church, evangelical, catholic and liberal and states:

What has remained constant, however, has been the Church's commitment to the faith 'uniquely revealed in the Holy Scriptures and set forth in the catholic creeds,' its maintenance of the traditional three fold order of ministry, and its determination to bring the grace of God to the whole nation through word and sacrament in the power of the Holy Spirit.

In other words, in Anglican-speak, what has changed is the absence of reference to the Articles as such.
...No one now has to assent to the content of the Thirty-nine articles, and I'm saying that as someone who has measured himself as being outside the belief boundaries of the Church of England at the liberal end.