Alrite pal, its a nice head banger this one because you have checked all the main components physically id say its a sensor side of things.
The only other thing i can think of is maybe the intercooler is block up and not letting enough cold air through it, so the car is acting like its got no intercooler (ie 75bhp model) The way i would check is to disconnect the drivers side pipe and place my hand near the intercooler end to feel what is kicking out. You have blanked the egr valve already so it cant be that unless you did not block of sensor. Way i was told to trick the sensor is to move the little black air feed pipe which went to the top egr valve and hooked up to the ref side of sensor (drivers pipe) just remember to plug both of the old pipes up which went to the sensor.(sorry cant remember name of the sensor)

Were abouts in dalton do you live in because next time im down ill nip to yours to compare your car to mine, to see if theres anything obv different or wrong