I am not a historian in any way, shape or form, so I asked my brother Andy [##48058]:
Who would have knighted Sir Walter Maliphant and similar people of that era ?
This is his reply ….
The King approved titles and major land holdings.
Knights were expected to follow a certain code in the days of chivalry – practice at arms, piety, support the poor and defend the weak etc., but there is an air of romance about all of that!
The Maliphants held their land as a Knight’s Fee (in one case half a fee), mostly from the Earl of Pembroke.
They were expected to be available for certain duties (defence) in return for enjoying the income from the lands in question (e.g. Upton).
When the Earl died (e.g. Aymer de Valence in 1324) there was an inquisition post mortem for the crown to review the state of affairs and confirm it (or otherwise), and Maliphant holdings appear in these documents.
Whether there was some knightly ceremony – particularly when a Maliphant son came of age or inherited from his father – is not recorded, but I would expect it would have been with the Earl not the King.
When there was a new King, senior Barons would have to declare loyalty, such as at a coronation, but I doubt every lowly Knight in the land turned up at Westminster to be re-dubbed!
Knights would have been effectively reconfirmed when their own Lord died.
Some research adds that while in earlier times someone could be dubbed a Knight in honour of some valorous deed (even by another Knight), later on keeping land in the family became more prevalent in terms of Knighthood. There is a whole development from people holding land from the King in 1066 to the freehold that current Barons enjoy, but death duties remain!
The main thing is to forget the romantic Ivanhoe stuff, these guys were deadly serious about their way of life, and things changed a lot as the old feudal society transmogrified into the modern era over several centuries.