Waiting 12months only to be told 4 days before you collect your car, not only the model has changed and the AP has changed is not only wrong but also bad business ethnics.
Its also worth remembering the GS line is a lower model to the Ultimate you have orderd and likely be missing more spec than the Ultimate as shown below:
Features over GS Line models:
PureSense
• IntelliLux LED® Matrix headlights with
advanced forward lighting
• LED front fog lights
• Front and rear parking distance sensors
• Advanced park assist
• Adaptive cruise control
• Lane positioning assistant
(auto models only)
• Side blind spot alert with flank guard
• Forward collision alert (all speed)
• Enhanced automatic emergency braking
• Automatic headlight levelling system
• Automatic high beam assist
PureConnect
• Vauxhall Connect
• Wireless charger for mobile devices
Comfort and Convenience
• Electrically foldable door mirrors
• Alcantara interior seat trim
• Moveable boot floor
Styling
• Black upper window moulding
As others have said ring motability ASAP. You can also cancel the order and extend the lease on your current vehicle. Some manufactures still provide you with the car you ordered even if was taken of the scheme after ordering even if it meant having having a 2023 model.