You can see the video of Paul Williamson's one-man protest here:
In summary, Williamson appeals to the Bible. Sentamu appeals to the will of parliament.
And there is the ultimate fact in the governance of the Church of England, captured in 30 seconds: its ultimate law is not God's law; it is the law of man.
That may not be what everyone in the Church of England would like, or personally believes should be the case - but that is the actual constitution of the body, and it's not going to change. What matters, finally, is not what the Bible says - it's what parliament votes for.
That is a large part of why, as I said in my earlier post, I find the Church of England to be a church whose fundamentals are unacceptable to me as a Christian.