Congratulations on having a degree.

Citizen's arrest and defense of property were not issues that were raised at this trial - the defence did raise the issue of self-defence, but that's because Cameron was said to have assaulted Emery immediately before the stabbing, not because Emery was defending his property.

Citizen's arrest could have applied, since the offending took place at night and there is no restriction in terms of prison term length for citizen's arrests at night:

Every one is protected from criminal responsibility for arresting without warrant any person whom he or she finds by night in circumstances affording reasonable and probable grounds for believing that that person is committing an offence against this Act.