Capital Gains Tax on Discretionary Managed Account

Selling a Managed Account, purchased for say 500 and sold for 570. Need to pay capital gains tax on the gain of £70k. HMRC return asks to list each share fund buying and selling costs but this impossible over many years of portfolio holding. The gain is straightforward based on the net sale proceeds less the cost of initial investment as there were no withdrawals. How can I declare the gain simply in a return to HMRC? Thanks.

Hi
You can declare it as 1 disposal but include an attachment giving the breakdown .

The attachment will just be the Sales Price - Purchase Price - the original purchase and sale documents are available. Trust this is adequate?

Hi Michael Hamlyn,
A calculation of the capital gain figure can be submitted.  HMRC may enquire into this at a later date and may ask for further evidence to support the calculation.
Thank you.