The overhang seats are constituency seats, or at least a person, because overhang seats come into being if the party has one more constituency seat than it is entitled to, according to its share of second votes, party votes. So this party gained no list seats, has no list seats, though all seats are constituency seats and you cannot identify the overhang seats. You cannot say there's a specific seat that is an overhang seat. You only can say this party has three mandates more than it would have gained according to its share of second votes, but you don't know which three seats these are.
On August 31st, 2016. See this statement in context.