Peter Howell
First of all make sure that you explain exactly what part of the work that you are disappointed with always a good idea to put this in writing also be clear that you are happy to pay once the problems are sorted out Give these trades people the opportunity to talk with you to try and resolve the issues so that everyone comes out happy If they refuse to return to discuss the issues with you then you will have to inform them that you will employ an independent surveyor to access in a professional manner if the work is indeed below standard But by far the best way is to talk talk before it all gets nasty and drawn out and expensive Good luck I hope you get the issues resolved