Well to close this thread down, we had piston 4 confirmed as failing/failed so we advertised it explaining the issues and a guy has bought it with the intention of putting an engine in it. To be honest I'll be glad to see the back off it and I won't be buying Korean again that's for sure. Never had so many issues with a car. In 6 months it's had a slave cylunder, master cylinder, two injectors and then a cylinder go. Lesson learnt me thinks! Thanks for everybody's help and input, it's much appreciated.