CGT Discount on LTI Shares, page-6

For CGT purposes they are acquired on the date you receive them, not the date of the plan. This is called the taxing point. It is the first time there are no restrictions on sale. They are taken to be acquired at market value on this date. You need to hold for 12 months from then to access 50% discount.

If you sell with 30 days of acquisition they are not taxed under the CGT regime. Rather you adjust the discount to be the difference between the proceeds received and any cost paid for them.