Before David came to see Arthur, the British Government surely had made preparations and considerations in advance.
Australasia would not help the United Kingdom for nothing, even though the relationship between the two countries indeed was good.
Still, the same old saying applied: between nations, only eternal interests exist, not eternal relationships.
To maintain good relations between Australasia and the United Kingdom, satisfying mutual interests was a necessary prerequisite.
This saying could also apply to interpersonal relationships among people. Aside from the elements of kinship and love, to maintain a relationship with a regular friend, respecting mutual interests was very important.
When you are very important to someone, you are that person's friend. And when someone is very important to you, they are your friend.
Humans are like this, most of the time there is no absolute selflessness, only the satisfaction that comes after mutual interests are respected.