I pay the CSA they hold it in their bank for seven working days - so they get all the interest - then pay it to the father.
At the end of each year all the accumulated interest is paid to the government.
As Mc Noodle says 15% for one child 20% for two etc. You can check the csa website but they have started taking interesting information off! They used to have information regarding Advance Payment but it seems to have disappeared and nobody seems to know anything about it!
Website:
http://www.csa.gov.uk/
Give me a shout if you need any further info on CSA have been dealing with them since '93 and I am nearly an expert, anyway I know more than the advisers do! Lol
BB xx