First it depends how the fan works, sometimes they have a belt and run continuously, Next it may run electrically and will be temperature controlled, or the really posh cars have a system where wax needs to melt to run the fan.
Temporally there are a couple of things you can do (1) put the heating on inside the car at full heat and blowing hot air at max , you might have to drive with windows open but this will defiantly bring the heat down in the engine. (2) Take the thermostat out and run it without one,so it is cooling all the time not when the thermostat thinks in should.
I used to have a Hillman Imp (WHAT) you say, this was a small English car with the engine in (how you say it ) , the trunk, we call it the boot. It was a water cooled engine. You could change your car to a VW BEATLE, they have their engines in the trunk and they are not water cooled.
I used to do all these tricks when I was young but now I drive a BENTLEY, NO MORE PROBLEMS..........................