Calculating CGT payable on demutualisation shares and those subsequently bought (DRIP)

Several years ago, I received free shares under a demutualisation. I bought further shares under an initial offering and I subscribed to the DRIP scheme so that all my dividends were reinvested. I declared my dividend earnings each year on my SA return. I have now decided to sell the shares before the CGT allowance is reduced again next April. The current share price is substantially lower than the initial block purchase price and also lower than many of subsequent DRIP purchases. I wondered if there is an online calculator available which would simplify the calculation, or at least a formula which I can apply to my figures to determine CGT liability? TIA.

Hi John B54,
There is no online calculator for this, but you can work out any gains / losses by following the guidance here:
Work out if you need to pay
If you have a gain to report, then you can do so here:
Reporting and paying Capital Gains Tax
Up to 31 December after the tax year end, otherwise you will need to declare in a tax return.
Thank you.