William the Conqueror link?

I had read the history of Gidleigh village and manor in the Middle Ages in Tony Grumley-Grennan's book, and taken note of the family trees on Ancestry of the Prouz family that start with Giles de Gidley, but not really taken much notice of them. Then Pete Gidley sent me a copy this week of an extract from “Devonshire Wills “ by Charles Worthy written in 1896, pages 394-399. I reproduce it here:

"GIDLEY OF GIDLEY AND HOLCOMBE PARAMORE.

This ancient family derives its name from the parish of Gidley, on the north-eastern escarpment of Dartmoor, which land was given by William the Conqueror to his half brother the Earl of Mortain, and held under him, in 1086, by a certain " Godwin," and in the Confessor's reign it had also belonged to " Godwin," described as the " Priest" Westcote, in his seventeenth century View of Devonshire, declares that he had seen a grant of this land, by " Martine," Earl of Cornwall, in favour of his " nephew, Giles de Gidleigh,'' the seal bearing the impress of a triple towered castle, and that the said grant was "exemplified, under the great seal of England, in the reign of Henry VIII."
The said " Giles de Gidleigh," to have been a " nephew " of the Earl of Mortain, whose brother Odo, Earl of Kent, and Bishop of Bayeux, had no issue, should have been a son of his sister Emma D'Abrincis, the mother of Hugh, Earl of Chester, and there is no record that she had such a son as "Giles." Robert of Mortain, Odo, and Emma were the children of Harlotta of Falaise by her marriage with Harlowen de Conteville. Their half-brother and sister, King William and Adeliza, were the offspring of an earlier, and less respectable, intimacy on the part of Harlotta, with Duke Robert of Normandy, and it is most probable that the several personages who have been handed down to us as " nephews " and " nieces " of the Conqueror, or of Mortain, such as "Albreda," wife of Baldwin de Brion of Okehampton, William " Warlewast," Bishop of Exeter, and this Giles de Gidleigh, were children of the king's whole sister, Adeliza de Falaise aforesaid, who was married thrice, and had issue by each marriage, inter a/us, Adeliza, Countess of Albemarle in her own right, 1081-1090 ; Stephen, who succeeded his half sister in that earldom ; and Judith, wife of Waltheof, Earl of Huntingdon. The daughter of Albreda of Okehampton was also called Adeliza, and doubtless so after her grandmother. It is certain that this Dartmoor property descended in the name of Gidleigh for some generations, and down to the middle of the fourteenth century, when the daughter and heir of Giles de Gidley married William, son of Waiter Prouz, by the daughter of the Lord Dinham. Her eldest son and heir succeeded to Gidleigh, and his only child, Alice, married, first, Sir Roger Moels, and, second, Sir John Damerell. The latter family inherited Gidley for several generations, until it passed by intermarriage with one of them to the Coades of Morvell, in the county of Cornwall. It was during their ownership that Gidley Castle probably fell to decay ; the remains of it appear to be of early fourteenth century date, and consist chiefly of the large square keep, the lower chamber of which is barrel vaulted, and has two newel staircases communicating with the upper portion of the building. The name of Gidley, however, appears to have been preserved by a younger branch of the family which settled at Winkleigh, the Devonshire seat of the Honour of Gloucester, upon a property called Holecombe, which had been held under those Earls by William de Portu Mortuo in the reign of Henry III., and was afterward corruptly known as Holcombe Paramore. Richard Gidley was buried at Winkleigh, 26th March, 1574."

Tony Grumley-Grennan is not convinced by the supposed grant of the manor of Gidleigh by Martin, Earl of Mortain to his nephew, Giles de Gidley. The language used in the grant is apparently not from early Norman times, but more likely to be legal language from the 13th and 14th century.
The Prouz family tree produced from Charles Worthy's account also differs in some respects from other Prouz trees I have seen. It is unlikely that it will ever be proved that the Gidleys of Winkleigh descend from William the Conqueror's mother. That there is a link with other Norman barons seems highly likely, however. Manors weren't granted to Saxons or peasants.
The supposed link between the Gidleys and the Coades family of Cornwall is worth investigating, and I shall be checking the Visitations of Cornwall on my next trip to the Society of Genealogists, and trying to contact some Coades family historians, to see if I can find out if the Gidleys of Holcombe Paramore really were a younger branch of the Coades family.