Dakota,
Dakota I have both a green single front Challenger (actually painted red!) as in the photo and a red single front. They were made especially for the British market with our narrow rowcrop widths. The V twins were never sold in the UK. As far as I am aware the British single fronts were made in the UK and fitted to imported USA made tractors. Just a very few of them have been found in the USA and were presumably so adapted for the same reason.
In the UK the single fronts were shown in MH brochures but as far as I am aware never in the USA.
John