My ex husband is earning a better income than he did when he was working, and my son is turning down work at 17 to provide him claiming child support from me for as long as he can (plus a staggering eight thousand in benefits on top!) How can I stop this?

The biggest problem here is can you actually prove what youre saying here in court with solid evidence and if so contact your child support collection agency or challenge him in court. Chances are it will all come to end once your son turns 18 anyway but check your support decree for sure

.  Good luck