I've answered my own question, thought I’d post this info in case its of use to anyone else.
Apparently, the PWC will be given the option of transferring to the new system or set up a private arrangement on the current csa calculations. The transfer to the new system will take 3 years so will be finished in 2013/14. But all new claims after April 2011 will be based on gross salary. I've worked out my partner will be considerably worse off a month under this new system. How many PWC aren't going to want to swap to this new system and how many private arrangements will have to be changed to be based on this new calculation? The percentages haven't been reduced that much only 3% for one child which nowhere near covers tax, NI and pensions! The amount that can be deducted for other children the NRP is responsible for has also been reduced from 15% for one child to 12%. So realistically everyone paying
child maintenance will be worse off, everyone receiving it will be able to buy more shoes and vodka!
New system April 2011
(1) Subject to sub-paragraph (2), the basic rate is the following percentage of the non-resident parent’s gross weekly income—
• 12% where the non-resident parent has one qualifying child;
• 16% where the non-resident parent has two qualifying children;
• 19% where the non-resident parent has three or more qualifying children.
(2) If the gross weekly income of the non-resident parent exceeds £800, the basic rate is the aggregate of the amount found by applying sub-paragraph (1) in relation to the first £800 of that income and the following percentage of the remainder—
• 9% where the non-resident parent has one qualifying child;
• 12% where the non-resident parent has two qualifying children;
• 15% where the non-resident parent has three or more qualifying children.
(3) If the non-resident parent also has one or more relevant other children, gross weekly income shall be treated for the purposes of sub-paragraphs (1) and (2) as reduced by the following percentage—
• 12% where the non-resident parent has one relevant other child;
• 16% where the non-resident parent has two relevant other children;
• 19% where the non-resident parent has three or more relevant other children.”
Sorry for hijacking your thread Chris, but hope this info helps you too.