I left my ex in '95 and he paid nothing until 2006. I went via the CSA and fought hard to get any where with them as they did with him. He left job after job as soon as bosses told him the CSA were about to garnish his wages which meant once again they had to start from the beginning. He owe'd over �10,000. The CSA can find him via is NI number or tax records
I did get a payment in Dec 06, 11 years after I first made a claim - �5,000 in a lump sum. Why? Because I told the CSA I wanted to make a claim for compensaiton against them for mismanagment of my account. 6 months later, I got half of what he owed me and I was happy with that.
Generally speaking though, the CSA are poo!