Hey Bindi. the Scangauge wont show EGT's because there is no factory fitted pyrometer on the Patrols, same as for the oil temp gauge. Technically your EGT's should be lower when blocking the EGR as your now not getting hot exhaust gas pumped into the cylinders, which would prior to the EGR block create slightly hotter exhaust gases.
Adding a Dawes and needle valve to the CRD's is not as important as it is with the Di's as the Di's ECU had a real hard hard time trying to properly control boost levels and spool up rate. But using these two valves in a CRD many have found they are able to control the max boost and spool up rate much better than what the factory ECU can. Therefor making the car run even better that stock. Just because the car is new'ish doesn't mean its right. Just to what is right from factory and to Australian design. Same applies with any car, petrol or diesel. Hence why there is so many aftermarket add on's for any new car you see on the market. Simply to make them better from what you get out of the crate.