Capital Gain cost on employee incentive shares

Dear HMRC, I obtained incentive shares at zero cost from a company I worked with a few years ago, before I became a UK tax resident. I am no longer with that company. I am referring to HS287 but not sure how to determine the capital gain cost, if I were to dispose these shares later. There is no restriction on the time I sell them. I can keep them or sell them at any time. Also, there is no risk of forfeiture. So, it seems the capital gain cost should be the actual cost, which was zero; however, HS287 also mentions that, in general, the cost is the market value at the day I obtained these shares. May I have your help, please? Thank you.

Hi ,
 

As you did not pay anything for the shares your purchase price is nil  . Thank you .