Hey Jackie,
Do you think he is being difficult or can he really not afford this?
I'm in a similar position. My daughter went to live with her Dad four years ago. Because when my daughter lived with me I wouldn't meet him halfway to collect her he will now not do it for me, even though I earn a lot less than him. In fact he is deliberately difficult, I can't phone home phone have to phone mobile, he's lied left right and centre. I have finally come to terms with the fact that not everyone wants to be reasonable!
I have gone down the variation route around four times and have always been unsuccesful. I have to spend at least �15 per week visiting my daughter before they will reduce my payments. I currently have around �30 per month once I have paid rent, council tax, gas, elec, phone, petrol, shopping. I have no debts, credit cards, loans etc.
Life's a bitch but hey!
BB xx