NCT - Vehicle Management Light - Yellow Light

Hi, i have a octavia and the engine management 'yellow' light is on, got it checked on the diagnostics computer and it pointed to either cat converter or mixing sensor from exhaust is about to fail,

Can you fail the nct for having this light on ? as i have a test coming up and both issues are high cost to fix and do'nt want to bother if not, thanks

The EML on its own is not an NCT failure, but with faults showing up in the sensor or the cat, the car may fail the test on emissions. Am I correct in assuming its a petrol car?

yes its petrol, thanks