Regardless of what sign the WCB chose, there has been the option of putting something fitting on the back of it, with a simple message saying ‘farewell’

The SH2 welcome signs in Dannevirke say Farvel on the reverse sides which is the Danish/Norwegian spelling of Farewell, plus a road safety message.  (The Scandinavian spelling of Welcome — Velkommen — would be comprehensible to English speakers, too).

If the WCB goes ahead with the fence/pipe organ design, then another plaque saying ‘farewell’, perhaps with the Maori ‘hei kona ra’, on the other side would be a minor and worthwhile addition.