Originally Posted by Stuart@VelocityAP

I know British Automotive Repair and they are good people. They are not the kind of place to use underhanded tactics to create work for themselves.

O2 sensors do need replacement, and codes can sometimes be transient when things are on the edge of efficiency or failure range. It's possible that the codes might not come back on for a while, but have 100% confidence that if they stated that something happened, they are telling the truth.