Prince of Prospect
Prince of Prospect (or Princess of Prospect, if female) was the term used for the first person in the line of succession to the Talossan throne eligible to serve as King during the long period during which the throne was hereditary.
The person who would be the current Prince of Prospect is Patrick, followed in succession by Peter. To be eligible to the throne, a person needed to have been a citizen of Talossa, which is the reason why Andrew Woolley, eldest son of the King and not a citizen of Talossa, would not have been the Prince of Prospect.
In this term, "Prospect" does not specifically refer to Prospect Avenue, the important street that runs through the nation of Talossa, although it can be said that the street was named for the Talossan heir presumptive.