I have a different answer which includes my own commentary. Take a look at pages 3, 4 and 5 of HS283 here.
You appear to have retired from the company 15 years ago. In order to qualify for entrepreneurs' relief, you have to satisfy the condition as set out at the bottom of page 3 of HS283.
You had over 5% of the shares and the company was still trading but unless you were an officer or employee of the company in the one year to the date of disposal of the shares in the last tax year, you won't qualify for ER.
If you were an officer or employee of the company in the one year qualifying period, then you may not have ticked the appropropate box on the capital gains pages to claim ER. ER will be ineffective where your net gains for the tax year are covered by the annual CGT exemption. The old ER used to be discount from the gain so that when CGT was applied at 40%, the effective rate was 10%. That system was replaced by a simple flat CGT rate of 10% for gains qualifying for ER made after 22 June 2010 as you can read on page 21 here.
I hope this helps but let me know if you have any further questions.
These interventions are quite un-necessary. If the questioner has retained his directorship even if he is not remunerated, and the question is silent on this matter, then the Relief would still apply.
I gave the correct answer by specifically mentioning the qualifying criteria. That's what's important. I never mentioned remuneration. All I mentioned was the requirement to be an officer or employee. The words "somebody's learning something new" come to mind.
I'm wondering why the other expert didn't give the qualifying criteria in his original answer. All of a sudden, it has become critical to be an officer or employee whether unpaid or not.
You might note that I also have the support of another expert.