Bit of a difficult one that Matt, my brother has rough idle at the moment in his clio and we can't find the fault at all, changed just about everything too but still no joy.
Start with the obvious, check the HT leads are all plugged in correct and try bending them with engine running to see if any are damaged or worn, if so then problem will stop suddenly, we pulled one out at a time with engine running to see if the problem got worse, If not then the HT lead or coil pack may have gone on that cylinder, just remember to be careful if you do this as it's high voltage so don't let the lead come into contact with anything on the car.
Another problem someone told me about was the leads becoming trapped under the plenum chamber, the wear and movement can cause them to rub through the outer sleeve.
