There is no way to fudge the emissions test here unless the garage has a "good" vehicle that they can use to stick the probe up. The test equipment is part of the DVSA computer system and the data goes straight to them. It is the DVSA that provides the pass certificate, not the garage.
And garages are secretly checked by DVSA testers, just like "secret shoppers".
This is the type of thing you get.
