Between the 14th to 17th century England had the War of the Roses and the English Civil War; but did it also have smaller conflicts where two nobles might fight each other beneath the kings notice? And if so how were such things dealt with by the crown?
Yes!
Most commonly would be raids, where a rowdy group would smash things, steal, eat and drink, rough people up. Lawsuits would be brought, and the various systems would be in place.
More seriously- and playing across the Wars of the Roses, were two feuds. William Bonville married Elizabeth Courtenay, aunt to Thomas Courtenay, Earl of Devon and received land that Courtenay ended up not wanting him to have. More seriously, Courtenay and Bonville were fighting for prestige. Bonville was on the rise, but Courtenay recieved a stewardship that got him a lot of money and had been Bonville's.
The resulting fracas meant that the king and council took the job from both of them until Bonville skipped off to France for fighting reasons. Then he came back, and it started all over again. Courtenay was originally a supporter of the Duke of York, which got him arrested. When he was released, York relied more on the Earl of Warwick, and Devon switched to support the King.
Then Courtenay launched attacks on Bonville, resulting in the murder of a man who switched to Bonville's side. Courtenay also besieged the city of Exter. This happened while the Duke of York was in change, so Courtenay and his sons were arrested. When he was chased away, the Queen decided Devon could be useful and released him.
Later was The Battle of Nibley Green. Thomas de Berkeley died, leaving only his daughter Elizabeth, who inherited her mother's titles and her father's fortune.
Well, what wasn't entailed. That legally was to go to James Berkeley, her cousin. This made Elizabeth and her husband, Earl of Warwick, very unhappy and started the longest lawsuit in English history. Which had a lot of raids and kidnappings. James Berkeley's third wife, Isabel, died in captivity.
In 1469/1470 (Depending on the calendar)... things had not resolved. At all. So Elizabeth's great Grandson, John Talbot, being eighteen and impulsive, challenged James Berkeley's son William. William was in his 40s and actually knew what he was doing.
William won, John died. William was not punished by the then king, Edward IV, who was fighting with the newest Earl of Warwick and probably found a new commander very useful.
The lawsuit didn't end there.