Sale of shares - CGT or PAYE after one year?

[tapetheescape]

Hi folks. I have some questions about shares/options I have and would appreciate any guidance!

I worked for a company in the UK from 2012 to mid 2017. During that time, I had share options that were granted and vested.Last month I exercised and sold some of those shares, and the company I worked for did a tax withholding of around 40%, which as I understand it will be reported by the company via PAYE. My question is - if I exercise and hold the remainder of shares, and only sell them after 12 months of holding, will there still be a tax withholding at exercise, or will I need to report the capital gain and pay the CGT rate of 10% or 20% dependent on the amount?

Thanks all!