CSA after Court Order

I was hoping someone could help with some advice. My partner has for the last 15 months been paying his ex what was reluctantly (she wouldn't settle without this) agreed in the CO as CM. According to the CSA calculator he is paying nearly £200 per month more than he needs and she is becoming increasingly difficult with money, asking him to pay all sorts on top of this, despite the fact that she is loaded. He has had enough and is tempted to go to the CSA now to vary this. I have a couple of questions, I have recently moved in with my partner and am employed but not paying him rent because I have a mortgage of my own that I have to pay. Can my inncome be taken in to account by CSA? Also, are there any other pitfalls of going through the CSA as the ex is a control freak and will hit the roof that he is taking back control here? Any advice would be welcome.

CSA payments are based on his income alone. I don't believe there are other pitfalls, the CSA can be unreliable and sometimes don't take payments, payments can take longer if you have the CSA collect payments and pass them on, so it would be better to have them asses the amount then arrange payment between you.

Child maintenace is assessed against your partner's income only. Once your partner applies to the CSA they notify the court and the court order ceases to have effect two months later.

One pitfall is that frequently in the past when the non resident parent has applied to the CSA is that they are told the CSA cannot take on the case if the parent with the majority of care doesn't cooperate. This isn't correct and appears to be down to an error or misunderstanding in the CSA staff handbook. If your partner is told the CSA cannot do an assessment for this reason he should ask to speak to someone more senior and better trained.