Hi!
Thanks for getting back to me so quickly.
Sorry for the WhatsApp confusion. The KSK app on my phone gave me three options to install KSK on the child phone: scan the QR code, copy and send a link, or install straight from the Play Store. After installing from the Play Store and getting stuck, I thought maybe the link or QR code might have account specific information. In any case, as you say, that does not seem to be what is causing the problem.
I get as far as the third screen in your post. When I click the "Activate" button, it sticks at "Receiving subscription info...". Screenshot below.
Thanks,
Derek