No idea, but K-Jet is involved, so I'm going to guess emissions.
One rear flexi brake hose. Which was annoying as I'd finished putting the car back together to then take the rear beam off for a poxy hose.
Last year it had fueling issues but I did have use of a CO meter and got it bang on for the MOT, ran like sh*te though.
You may have placed a good bet as I have changed the WUR and set the car up by sight and sound this time.