Rubber Bumper Apron Slots

The air-dam, showing how it scoops air into the slot for the oil cooler and lower half of the radiator and will do so even when the bumper and hanging number plate is fitted. (MG-Cars.org.uk)

Raised number-plate opens up the slots in the standard apron. (V8 Register)

Air-dam slot, with the trunking around the oil cooler

Trunking forced into the same rectangular shape as the air-dam slot and lower part of the radiator to maximise cooling.