Not sure Ford officially made a Flat front RS2000 in the uk, I do believe they were available in some parts of Europe.
I'm not old enough to have been there back in the day, but as far as I know "most" flat front RS2000s were that way after having some sort of front end crash, be it light or heavy, and in those days a replacement nose cone was silly money, so they were rebuilt as flat fronts.
Someone may come and correct me but this is what I understand to be the most common reason.

Mike.

p.s. the 1 and only Mk2, absolutely love this car.