Is my boiler ID or AR

[Old UKPF 120233]

New qualified engineer has classed my boiler as ID due to flue CO 19.6 and CO2 of 0.0004. There’s not holes or defects or blockages seen, would this be at risk or is it dangerous? Last years engineer said it was ok but this young lad says no

 

[Knappers]

If your not happy then you should get a second opinion. Its not ethical to decide one way or the other without seeing your boiler as issues can compound to make an AR into an ID.
I'm also of the opinion that it's down to the engineer to make the call, where as some would see things a little more black and white.
There is no way in the world that I would downgrade a notification (not even if gassafe told me to) it would require another engineer to do that.