According to the wiring diagrams, there are the following earthing points.
G-1002 - Battery support
G-1003 LH Headlamp mounting panel
G-1004 RH Headlamp mounting panel
G-1017 Main Earth - Bracket steering column support
G-1018 Radio Earth - Bracket steering column support
G-1019 Electronic Earth - Bracket steering column support
G-1020 Tailgate
The three on the steering column support bracket I think from memory you can see if you remove the instrument cluster. I am not sure without looking if it is 3 separate connections, or if they all go to one point. The headlight ones are on the flat panel under the headlights and you can follow the battery connection to the one on the battery support. The one labeled tailgate - I am not sure about on a sapphire but I suspect perhaps the boot lid. Incidentally the taillight wiring shows as earthing to the main earth on the steering column - not the tailgate earth. I can only see this earth used for the luggage compartment lamp and switch, Heated rear window circuit including switch and the tailgate ajar sensor used for the alarm and the doors open display by the clock. Hope this helps. David