When options are exercised and sold, you pay income tax on the difference between exercise price and sale price, not CGT. You only pay CGT in relation to options if you exercise at a certain date (and pay income tax), hold on to them until they increase again in price and then, if you sell, you'd pay CGT on the difference between market value on the date of exercise and market value on the date of sale.
Buying shares is more tax efficient than options, because it's all CGT on any gain. However, the (potentially significant) disadvantage is that you have to pay for the shares in the first place, which increases your risk of loss if the shares don't increase in value. You don't have that risk with options as you can chose not to exercise them unless and until you know you are going to make money. If you are offered the chance to buy shares at a discount, then you do have to pay BIK on that discount now, and then CGT when you sell them in the future.
If you have to pay income tax on options, that tax has to be paid within 30 days of the sale date.