On my S, the engine bay temperature is also very high in traffic jams, and when I stop the car. I use to open the trunk for 10-20 minutes after each run in high temp conditions. I think the 2 header cats diffuse a lot of heat, even after the engine is stopped.
To prevent that, US and other hot countries cars have an additional engine bay fan in the right side intake (A132K0054F), wich is on when the temp is hot and the car stopped. It is standard in the Evora 400 (with a bigger fan), with the addition of a new rear undertray with spacers to have more air.
I would like to upgrade my english market Evora S with the bay fan. It seems that the relay is installed on every cars in the fuse panel, and I can see an electrical wire near the side intake wich seems to be the good one. Does anybody knows if it is simple to install it?