Hi Gillian, yes I am out here reading your very interesting posts! Happy New Year to you too (4 August today).
I am very tempted by your theory apropos Isabel Echingham being the wife of the elder Sir Thomas and not of his son Roger, and that Mary West is the first wife of Sir Roger who later married Alianor de Camoys.
I'm on a similar mission with the Lewkenor tomb at Denham, Suffolk, which has a composite Lewkenor shield of 12 quarterings. This is of Sir Edward Lewkenor, MP, died 1605, who married Susam Heigham of Higham and Denham, Suffolk, c 1569: he was the son of Edward Lewknor (III) who died a prisoner in the Tower c1556 for his part in the Dudley conspiracy against Philip and Mary; and Edward (III) married Dorothy Wroth.
Edward L (III) was of Kingston Bowsey Sussex, son of Edward (II) who married Mary Copley, and grandson of Edward (I) (married Margaret nn), son of Nicholas, who married Elizabeth Radmylde. This Elizabeth was daughter of Raffe Redmylde by Margareta de Camoys, sister of Alianore. This Nicholas Lewkenor is supposedly the brother of Sir Roger who married Alianore Camoys and son of Sir Thomas who married Phillippa Dallingrig.
Well the thing is that the Denham tomb composite quarterings INCLUDE the Echingham quarter, but DON'T include the delaWarre, Pelham or Audley shields such as are shown on the Carpet. I am not quite sure why some of the other quarterings at Denham ARE found there - Noell and Halsham, for instance, but I do understand why Doyley, Broos, Bardolph, Tregoze, Dalingrig and Radmylde are found: and the Echingham fits sensibly into the series. I suppose the Noell and Halsham may connect to the Wroth or Copley ancestry of Edward (IV) somehow (and that would fit with them being centre bottom of the Denham shield).
Anyway this makes perfect sense if Echingham is part of the direct ancestry of Nicholas and his dynasty of Edwards, whereas it is meaningless if Echingham is the wife of Roger, UNLESS one thinks that Nicholas is the son of Roger, which is also suggested somewhere. But then why not also Delawarre? No doubt something will come along to explode our haven of reason but just at present it seems perfect!
The shield includes 12 quarters in three rows of Four: The identifications were made by J J Howard in his Visitation of Suffolk, cited by Sydenham Hervey in his little publication on Denham Parish Registers (1904, Bury St Eds):
Top row: 1. Lewkenor: Azure, 3 chevronels argent, a mullet for difference. 2. Bardolph: Azure, 3 cinquefoils or. 3. Tregoze: Azure, 2 bars gemelles or, in chief a lion passant of the second. 4. Dalingridge alias Delahache: Or, a cross engrailed gules.
2nd row: 1. Broose: Gules, 3 bars vairce argent and azure. 2. Echingham: Azure, a fret argent. 3. Camoys: Or, on a chief gules, 3 bezants. 4. Radmylde: Barry of 6, ermine and gules.
3rd row: 1. Doyley: Gules, 3 bucks' heads caboshed or, 2 and 1. 2. Noell: 3 pales gules in a field or. 3. Halsham: Argent, a chevron gules between 3 torteaux 4. Lewkenor: (as above).