UM ! , I would ask very nicely if they can point you to the ITV test manual , so you can read that . This is a freely available on line manual in the UK .
I would find someone with a diagnostic machine & perform a live data read , all the better if driven on the road , you can actually see the values the lambda sensors are returning & which one is dying / faulty .
You may could also simply ask the ITV examiner about testing on LPG , they might well be happy to do so
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To stupidity & beyond
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