CGT when unable to find price paid for company shares.

While working for my last employer before retirement I accrued a number of shares through ‘sharesave’ and bonus schemes. I have traced the price I believe I paid (strike price) for some of the shares (CSN). I have three lots of Ordinary shares that I cannot find. I have calculated the average in what I believe is my Section 104 holding, using the strike prices I have available. I have tried obtaining these prices through the three different companies who have looked after the shares. All they can tell me is market price when I left company. Where do I stand if/when I sell some/all of shares?

Hi Gazzafmc,
For the ones you cannot find, you can contact the London Stock Exchange for details.
Thank you.