Hi David,
A Zone Reference Point will only be visible if the zones have been placed using an automatic recognition method (Inner Edge/Reference Line)
If there is no Zone Reference Point visible then the Zone may have been drawn manually.
You can double check how the zones have been drawn by using the Update Zones command, if you see the icon as per the attached image then the zones will have been drawn manually.
If the zones have been drawn manually, you can simply select them and flip them to the Inner Edge/Reference Line geometry methods and this will show the Reference Point. (That's if however the zones are bounded correctly)
Kind regards,
Marcus