William Marshal and King John's suspicions: 12th century dark deeds

Today's research snippet. 

Back to King John's letters today, and at least one concerning William Marshal that shows John's paranoia and the tensions between the men. John obviiously suspects William of plotting against him. These are a series of letters from August 1212 when John was planning his campaign against the Welsh, a campaign that was aborted following threats to his life where he received secret information that he was to be assassinated in Wales. Was this a murky unknown moment in William Marshal's career. Was he part of the plot to overthrow John, or was John, beset by shadows, seeing even more of them than existed? 

The King to Ranulf Earl of Chester, greeting. We command you to maintain and protect Madoc ap Griffin and that you offer not, nor suffer to be offered to him or his, any injury or grievance; for when Llewelyn withdrew from us, to him would we recur as to our son. Witness ourself at Shrewsbury on the 3rd of August

The Bishop of Winchester is commanded to send the King the iron caparisons, which he gave him, so that he have them at a Nottingham by the Sunday next after the feast of Saint Lawrence. (12 August).

The Sheriff of Hereford is ordered to surrender to the King two pair of iron caparisons, the two coats of mail, and one hauberk, as Peter le Burgess deliver them to him, so that the King have them at Nottingham on the Sunday next after the feast of Saint Laurence. Teste 5th August at Woodstock. The King arrived at Nottingham on the 14th.

The Sheriff of Oxford is ordered to cease his demand upon William de Mesnil-Neuf for the supply of men with spades and hatchets, for the said William is summoned to go with the King in his army into Wales. Attested by the King at Woodstock, 6th August.

Know that we have granted to all the family of Llewelyn permission to come to us at Chester, on the Sunday next after the ensuing Assumption of the Blessed Mary (19th of August), or before, to give us security for his faithful service, namely, such a that he cannot hear after receive from his allegiance. And in testimony hearof &C. Witness ourself at Lamport, on the 11th of August in the 14th year of our reign.
The King to William Marshal Earl of Pembroke, &C. We command you that together with John Lord Bishop of Norwich and other our lieges of Ireland, ye be with us at Chester on the Sunday next after the ensuing Assumption of the Blessed Mary (19th of August).

The sheriffs of England are commanded to summon all whom hold of the King by serjeantry, to be ready at Chester with horses and arms to go into the King’s Service (19th of August).

The King to Brian de Insula &co. We command you to send to us at Nottingham all the oxen and cows which you should have sent to Chester for the supply of our army. Witness ourself at Northampton on the 16th of August.

The King to all his earls and barons who shall see these letters. We return you our thanks for that you shall have come so powerfully in our service to Chester, but since we cannot at present to go thither, by reason of certain affairs which have recalled us, we inform you that you may return to your respective homes, with your knights and people whom you brought with you, for which our thanks to you are manifold. Witness ourself at Nottingham on the 16th of August in the 14th year of our reign.
The King to Geoffrey de Lucy &C. We command you, immediately upon sight of these, to send eighteen of our galleys by Chester, round the coast of Llewellyn’s land, to destroy the ships, galleys and boats of our Welsh enemies, and to do them injury in every possible way, but be always on your guard lest harm should come to you from the land or power of William Earl Marshal; and send to Bristol two galleys with our provisions, and some persons who can conduct them, and send us word when they arrive at Bristol; and if you are in need 
of money let us know it. Witness ourself at Nottingham on the 17th of August.