You should know that the Victoria Cross (and the George Cross) are both considered to be superior honours to any Knighthood.
Knighthoods are generally not awarded for single acts of bravery on the basis that most Orders are only permitted to have a limited number of living members - and if Knighthoods were handed out for acts of bravery, then in large wars (such as either World War) a situation could develop where soldiers who performed particular acts of bravery at the end of a war might not be able to be admitted to the same orders as those as performed similar acts early in the war, due a lack of places.
Just following up on this - another observation.
This is the New Years Honours List - which occurs every year, as one of two occasions when a large number of Honours are announced (the other is the Queen's Official Birthday).
While awards for servicemen and women can, and are, announced in the New Years Honours list, it is quite common for significant military awards to be announced at other times - Private John Beharry's Victoria Cross, for example, was gazetted on the 18th of March 2005. By announcing such awards in this way, it avoids them being 'lost in the crush' of other awards.
Also, it's quite common practice for a significant number of additional awards to be made at the end of a war to cover any people who were missed.
familyop,
A Knighthood is essentially a lifetime achievement award. As nauturalman1975 said, awards for valor, particularly the Victoria Cross and the George Cross take precedence over all other awards.
Naturalman1975
Only some orders of chivalry have membership limits, the Garter and the Thistle do. The orders of the Bath, St. Michael and St. George, and The British Empire do not. I'm not sure about the Royal Victorian Order.