I have been thinking about this constantly today and must say that all your words of widom and encouragement have spurred me on to see this through.

There are factors that need to be tested but its all to do with vacum...

A scoop system mounted under the car where the Fiesta mk 3 fuel tank would normally sit will force the air underneath the car to flow at a gradual pace up into the boot area where a rad will be placed at a 45 degree ish angle. This rad will need to be encased.

1 to reduce temps and further heat soak in the boot area.
2 to keep the vacum effect (sealed compartment).

the air flow will then via two fans constantly running aid the air flow to leave via vents in the rear tailgate/ valence - which ever is feesable.

The Naca ducts as in escosracer - car and leif neilsens will be ajoined to the sealed vacum box and keep air going to the rad.
I origianlly thought this was feeding the rad cool air. But due to aerodynamics and flow of air in this area it would not flow enough to cool a rad.

However these ducts in the rear quarters as not scooping air they are the vacums. The vacum caused by the air rushing under neath through the scoop box into the boot sealed box will pull air through these window vents and basically pull more airflow over the rad.

Obviusly all theory at moment, until i can speak with one of the norweigan crew.
It sounds to me - although un-trained and just plain hopefull a pretty good way to make it work.

If any one saw the scoops on my sunroof to direct cool air onto me during track time this could work for the rad too if nice carbon ones were made for the rear roof section....