Just another newbie experience, hope it helps.
I just started my Stashaway account today, and high risk portfolio was locked away from me too.
First I Whatsapp'ed them asking for further input, they told me to wait for a business day for replies due to high load on customer support.
Being impatient, I went to read the FAQ and found the SQX quiz, I spend about 90 minutes and luckily scored 100%, I screenshot it and send to Stashaway Whatsapp. The questions are relatively straight forward and the numbers are simplified in the question examples, and you can freely go back to read notes before clicking next and try to answer the question again.
Within 10 minutes they replied me saying congratulation and will enable high risk access in 2-3 business day.
Feel pretty smooth, the whole process is maybe half a morning or less.
I just whatsapp them and they told me to watch the videos. I told them I already did that. After that, I have to wait 2-3 business days. I guess that is next week.