Thanks for your response, after i posted this, I took the car back to the mechanic to have the fault codes checked and none showed up. However, i decided to risk it and drive from Dublin to Longford, during the way for about 10 seconds two seperate time I noticed it struggling continuously and thats when the CEL came on flashing but after I changed speed it smoothed out and the CEL went away immediately. I let it rest for the night, this morning I decided to check for any fitting errors. I found that the air intake duct/snorkel was not properly fitted in the front, so it would've been sucking in the warm air of the engine bay which could cause the engine to struggle under stress. Though as far as I'm aware, this wouldn't cause misfires or CEL but this points towards the previous owner or his mechanic being very rough with their work. (This car has had the internal speakers, headlamps replaced, wiring damaged, connector damaged and incorrectly replaced spark plugs, so someone has been frequently toying with the internals) And this prompted me to check other fittings. The intercooler pipe(?) (image attached below had some issues which I don't know if they could be a clue or not. The right rubber part attaches securely to the middle plastic bit, its nice and tight, however, at the other end of this rubber bit (the far right of the picture, where it would connect to the intercooler) there is a bit of give. I can wiggle it a little. Then the shorter rubber tube (at the left of this image, which goes behind the engine, so I'm guessing connects to the turbo) had slight greasy residue where it connects to the middle plastic bit. Sorry for the word vomit, am I on to something? How did the mechanic even miss that the air intake duct wasn't seated correctly, and surely if they just ran their hand along the rubber tubing here they would've noticed the grease.