I received a reply from Ultragauge, to my query about the UG not finding DTCs.

UltraGauge requests and displays trouble codes according to the OBDII standard. If no codes are found, it must mean that the vehicle's ECM has no codes that fall under the OBDII or the ECM is not fully OBDII compliant in this regard

So according to Ultragauge its a Landrover thing

The ultra guage is great for looking at engine data, but I wouldnt rely on its capabilty to detect or clear fault codes