Langdon Abbey (Premonstratensian)

Well, we have to include this one. The Premenstrualtensions were Augustinians of a sort, anyway.

VCH Kent says:  "The abbey of St. Mary and St. Thomas the Martyr, Langdon, was founded by William de Aubervilla and colonized from the abbey of Leiston in Suffolk. The founder, by a charter which is witnessed by Hubert, bishop-elect of Salisbury, and must therefore belong to the year 1189, with the assent of Maud his wife and his heirs, granted all his town of Langdon for the making of a Premonstratensian abbey by Robert, abbot of Leiston, and gave to it the churches of Langdon, Walmer, Oxney, and Lydden, for the soul of Henry II and the souls of William his son, Emma his daughter, Hugh his father, and Wymarc his mother, and Ranulph de Glanvilla and Berta his wife. The phrasing seems to indicate that Henry II was then dead, and in that case the date of the foundation must lie between 6 July and 22 October, when Bishop Hubert was consecrated."

The seal is from the late 13th century, and is now in the British Museum.

And here is the BVM and Child:

And on the other side, the murder of Thomas Becket.