by RAL on Tue Jan 24, 2012 6:08 pm
Payment on account for a tax year is based on tax due for the previous tax year. The tax due being tax liability less tax deduted at source. No payments on accounts are required in respect of capital gains tax. CGT is due and payable on 31 January following the year in which the capital gains was made. Therefore gains made in 2011/12 is payable in one lump sum on 31/01/2013.
You can reduce the payment on account based on your expected self employed earning. But do remember that if you do if the self employed earning turn out to be higher than £20k you would end paying the interest. There are some information on HMRC's website have a look at them
RAL