Holden VF Leaking Coolant From Above Transmission - Found & Fixed

Holden VF Leaking Coolant From Above Transmission - Commodore - Calais - What has failed and where to locate the issue. Customer complained of loss of coolant but could not find where it was coming from. The failed parts are o rings from the heater pipes that bolt onto the thermostat housing. It is labour intensive but a cheap repair if only replacing the o rings.