You're right in what you...

Ive got the 5 bonnet slots, plus the intercooler slot, and flared side arches....

Although, having checked yesterday someone has suggested it could be the thermostat...

I found,
The top hose hose HOT (possibly from conduction)
Top 2 inches of rad HOT
Rest of radiator COLD
Fan cuts in and blows COLD air off the rad
Bottom hose is COLD

Might try with out the stat and see if it makes a difference before i shellout STUPID money for the 4x4 Thermostat...