Many of the important church councils of Anglo-Saxon England were held at Clovesho, which has been called “the most famous lost place” of that time, because no-one knows for sure where it was – which is remarkable. A good candidate is Brixworth, just across the border in Peterborough Diocese, where a mighty Anglo-Saxon church still stands and from which a fellow-suffragan takes his see. (Read more at https://en.wikipedia.org/wiki/All_Saints%27_Church,_Brixworth).
A crucial council was held in 747 when much English church practice was brought into conformation with that of Rome, and a copy of the decrees from the council was in the great Cotton Library which was badly damaged by the fire of 1731 at Ashburnham House. (The manuscript of The Battle of Maldon was destroyed, and that of Beowulf was heavily damaged.)
Why not see if you read any of the text? Another copy survived so I can leak you an English translation of what’s going on:
“First of all [look for “IN primis” in line 1], the Metropolitan, as president, brought forth in their midst two letters of the Apostolic Lord, Pope Zachary, venerated throughout the whole world [look for “toto orbe” in line 3], and with great care these were plainly read, and also openly translated into our own language, according as he himself by his Apostolic authority had commanded”. (https://www.catholic.org/encyclopedia/view.php?id=3073)
With thanks to the British Library blog: