Just not paying

Hello. My daughters husband walked out of their marriage when one of their children was two years and the other was five weeks old. He was having an affair with a barmaid we found out afterwards and he is now openly living with her. He is self employed and claims to the new Child Maintenance Service that his earnings have dropped 70% in the last year. This is a lie because he has two cars, goes on holiday and drinks in the pub most nights. The C.M.S. have not managed to get a penny out of him since my daughter appealed for their help in March 2014. They say that he is refusing to disclose his bank details to them or even his current address. My daughter keeps calling them and offers to give them his parents address where his business apparently operates from, but they refuse to accept it from her saying they have their own ways of getting peoples addresses and bank details. If this is true it is taking an age. She has threatened to make a "formal complaint" but it doesn't seem to bother them much. Any suggestions how he can be made to pay and if he manages to fool them into believing he really is on his uppers will he have to pay more in due course if he earns more over the years?