Little Hawk, far be it from me to argue with anyone, (ha) but to call the 100 years war a British war is stretching it a bit. It was an attempt by the invaders/rulers of that island to recover lands usurped from them by the French, providing that you look at it from their point of view. Pretty much like the excuse given by China for invading Tibet, but a couple of generations shorter.

The Royal Navy was begun to keep Viking raiders down, and expanded to defend against Catholic-Church-influenced invaders at a later date and on several occasions. Once established, it was so obviously an asset that it had to be maintained, and unlike an army of that time, the hardware and personnel had to be developed and trained.
It is commonly forgotten or ignored nowadays, but religion was a factor in both the original invasion of Ireland and subsequent rebellions in that state. If England had remained Catholic, the history of those two countries would have been very different. However, Henry started his own church because the RC church already owned something like 1/4 of England's arable land, left to them in devout bequests by Norman-descended nobility.

My earliest comments concerning 'What to do with big military forces' are aptly demonstrated by the establishment of the British Empire, which, as (someone?Teribus? it's gone!) said, began a trading empire, but was backed up by military muscle when it met opposition in the form of locals trying to destroy it, limit it, or remove it's influence.
The fleet destoyed by the Kamikazi WAS Chinese, but organised against their will by their invaders, the Mongols.