Which year is CGT due on late payment of takeover proceeds as shares were lost/forgotten

When is CGT due on shares that were forgotten/lost and subsequently a search company finds the owner and pays the money due from a takeover (after costs) to the holder of the shares. Is it in the tax year when the takeover happened or the tax year when the shareholder actually receives the money. A second question is the tax due on the money received or the money before search company costs? Many thanks for any help

Hi,
Capital gains tax should be calculated using the tax year in which the shares were disposed of.  
Any tax deducted, should be declared, so that is can be factored into the capital gains calculation.
Thank you.