Ann: PDL 10 - Initiation of Arbitration Proceedings, page-8

Whilst it would have been nice to have had the matter resolved already.

Entering arbitration will at least gives us a timetable, and importantly halts any moves to cancel Stanley whilst the arbitration process is undertaken.
I believe that these types of arbitration processes are
a) undertaken by an independent (non-PNG) arbiter selected by the Minister and HZN.  The selection process may go something like this:  The Minister selects a non-PNG arbiter, and HZN selects a non-Australian arbiter.  These nominated 2 arbiters select the a third Arbiter who arbitrates the disputed Stanley licences.  So the arbiter is independent of the parties involved.
b) run under international rules/laws
c) the decision of the arbiter is final and binding on both parties.
So, assuming that HZN/Repsol are correct in their assessment of the merits of their case, then the arbiter should find in our favour.

It is still possible that the Minister can be satisfied prior to (and possibly during?) the arbitration process.  So a quick resolution is still possible.