From Wing Commander II on, we are occasionally reminded that our commanding officer is, in fact, Admiral Sir Geoffrey Tolwyn--indicating that he holds a knighthood of some sort. But what kind of knight is the admiral? Is he some kind of future space knight... or is he part of England's long history of chivalric tradition?
At one point in the prologue to Action Stations, ostensibly written by a future military historian discussing Tolwyn's career, we are treated to a short list of his most notable military honors (the rest of which we will revisit in a companion update). There we find the designation 'KCB'--which means that Tolwyn is a Knight Commander of the Most Honourable Order of the Bath.
The Most Honourable Order of the Bath (Wikipedia) was created by King George I in 1725 and is the fourth most senior British Order of Chivalry. It was initially founded as a military order but now includes a civil component. The order has three levels, of which Knights Commander are the second-most senior. There are nominally 355 Knights Commander at one time--but exceptions are allowed during wartime (galaxy-spanning conflict with the Kilrathi would seemingly apply).
We don't know what specific action earned Tolwyn his knighthood, but Knight Commanders who are Naval officers must hold at least the rank of Captain--which may suggest that Tolwyn was being recognized for his success at the 2639 Enyo Engagement.