Just found this on the forum, hope this helps
I signed up using my friend’s link, when will I get my free share?
If you and your friend have both funded your account with at least £1, you’ll both be eligible for a free share. We reveal your free share every Wednesday from 3 PM, but at the moment this will be spread over various days and weeks due to the very high number of them. Please wait at least 14 days before asking about your free share. Thank you!