Ah, the Dutton Sierra. That caused much confusion at the 1982 motor show where Ford launched their own similarly titled product to the British public.When I was a kid I remember helping my dad break 2 cortinas. A Mk3 saloon, and a Mk4 estate.
He was rebuilding a Dutton Sierra at the time and they were for parts.
The Mk4 Estate was a very fetching "hearing aid" Beige and was as rusty as an old horseshoe.