So what would be the limits...?

A revealing little exchange took place at the end of the early morning BBC Radio 4 Sunday programme [here] between the Bishop of Chester, Dr Peter Forster and the former Bishop of Oxford, Lord Harries of Pentregarth. It was pointed out by the Bishop of Chester that upon the passage of the current same-sex marriage legislation, for the first time the canon law of the Church of England would stand in direct opposition to the law of the land. 
Lord Harries also found that prospect worrying, but not for the reasons which would perhaps, for most of us, instinctively  come to mind, but, he seemed to say, because it is disturbing and unsatisfactory in itself that the Church of England would be out of step and out of touch with majority opinion in the country,  this then constituting one of the main  grounds for him to vote in favour of the current bill. Surely, that cannot be what he really meant to say - that the Church has to keep in step with public opinion?
But if we can take his words at face value, what, then, (the issue of same-sex marriage on one side) for the liberal establishment, of which Lord Harries is rightly regarded as being a prominent and distinguished member, would be the circumstances and the limits beyond which the Established Church of England (and, no doubt, its disestablished sister provinces) could not accommodate itself to majority public opinion in this  'democratic,' secular and, indeed, multi-cultural and multi-faith society? 
So, are there any limits at all? And if there are, by what criteria would they be decided? 
It would be good to be told before this sloppy, ill-conceived, dangerous and potentially sinister line of reasoning - a total abdication of all Christian ecclesial theological and ethical decision-making, offering a blank cheque to the zeitgeist - becomes the 'established' 'orthodoxy'.
Logically, admittedly in starkly different political and historical circumstances - at least at present,  it is hard to see any fundamental distinction between this position and that of the 'German Christians'  in the 1930s - that the Christian Church, together with its traditions and the interpretation of its Scriptures, should itself be subject to the popular will.  Another way of not being Church ...