Thanks for replies, i am back with an update.
Its turns out the CAT i had fitted was carp! Had it replaced with a approved one which was cheaper! Flew through the Test
Still have a problem with the juddering...`
She has had new plugs , leads, ignition coil, air filter, 3 mechanics scratching their heads, lambda sensor, temp sensors, injector cleaner
The engine purrs like a kitten when idling, and not too bad if you don't press her too much, but as soon as you want her to work she keeps coughing and farting.... I am at a loss, it feels like a never ending nightmare.
Since changing the ignition coil, she's not starting too well....any ideas?
Many thanks