Arwyn,
Thank you for your reply.
The original car was shipped to the US so it had the larger / squarer back plate on the rear, and on top of a full length bumper.
She is now in France so the plates are the same size as the UK, and although I could mount on top the bumper with a "amazon plastic" number plate holder attached on 2 metal pillars (originals), I was hoping that the original car were attached under the bumper.