OK, I went back and re-checked all my results, I activated the new EGR via the serial port and watched the feedback sensor output results as below. I then activated the EGR and watched for any drop in air mass meter volts (it was so small you couldn't really make it out on the scope!.
So I then scoped the AMM again against the O2 sensor output and it looks like the AMM is down slightly.
Question: does the ECU look at air mass as a feed back for EGR as per the old Vectras.