Like most eras, the neolithic period was not a peaceful time.
There are remains that have been discovered to have been killed with weapons including blows to the heard and arrows. Flint headed arrows have been discovered in places like Dorset and Gloucester. Bows were known to be used for hunting, so it isn’t a stretch to think they may have also been used in conflict or battle. Remains of a man found near Stonehenge was discovered with a protective wrist guard, which identified him as an archer.
The development of weapons also indicates a kind of arms race among tribes. Digs around the UK have found that different regions preferred certain weaponry, for instance, in the north swords were more popular, while spears were mostly used in the south west and the midlands. Hill forts are another piece of evidence of conflicts and peace in this era and Roman records have provided descriptions of chariots, which were used during the Roman invasion to protect the landscape. Remains of a two horse chariot that was dated back to the Iron Age was uncovered in Yorkshire alongside the remains of women, perhaps also indicating that there was much more equality in prehistoric society.