[DMitch16]

Hampshire is a big county. The N18 controls the secondary vacuum actuator solenoid next to the EGR cooler and if I recall opens and shuts a flap / bypass valve on the cooler to alter the EGR cooling demand. There was almost certainly nothing wrong with your old EGR valve and this may be the culprit. Loss of vacuum (bad actuator diaphragm / vacuum leak) or stuck bypass flap the likely issue.

 

[DMitch16]

All generic scanners say all the VAG models but they don't give accurate results only VAG-COM\VCDS does.

The Autel MaxiDiag MD802 All Systems does a pretty good job. Can read all modules, live data, freeze frame, measuring blocks, EPB basic settings, Oil / Service resets and some adaptations. Not to mention all the ODB2 codes and some special functions of almost all other brands on the updateable SD card supplied. All for £95 (Amazon priced it wrong - went up to £200 a day after it was ordered). Average price £160 - £180.

Not exactly cheap (except for the Amazon error) as it is nearer VCDS prices but it's one of the closest diagnostic tools to VCDS I have come across so far to date. They just need to add full coding ability and it would be as good. Bit more portable than my laptop and covers all other cars we have hence why I bought it.