Do a test and ditch the vented bonnet.
Cars are designed so that when moving, you end up with a high pressure point ABOVE the bonnet, and a low pressure point under the car. This helps in aerodynamics, but also has a MAJOR contributing factor to air flow through the engine bay.
Cars with lifted bonnets at the rear often come across an issue where they over heat, especially when being worked, purely because there is a MASSIVE high pressure zone at the back of the bonnet and air enters through here, and escapes under the car meaning not as much air actually flows through the IC and/or Radiator.
Try boxing as much of your air intakes at the front direct to the radiator/FMIC, as well as changing the bonnet, and throw a BRAND NEW fan and hub on.