£50 referral bonuses on investment plan

I have acculmated a few referrals through an invesment platform (wealthfiy). For each referral they give me £50 invested in their plan. My initial investments, along with my referral credits are sat in a GIA. My questions: 1. Is this capital gains tax? 2. Do I only declare and pay any capital gains tax once I have withdrawn from my investments? 3. Do I declare the whole £50 per referral and the gain made on each £50 as a gain? Thanks

Hi,
It is not Capital Gains Tax, but you would need to consider if it needs to be treated for Income Tax purposes. You can see guidance here:
SAIM8020 - Annual payments: meaning of annual payment
Thank you.