It was recently brought to our attention that everyone has a 24 hour mirror image of their production system available. Swap your domain for "yourdomain" in the link below - it's a snapshot from the day before that gets updated nightly, so any testing you do must be done day-of, otherwise it will be overwritten the next day! Same login credentials as the live site.
https://"yourdomain".lm.bbk12.com/app/#login
However, we can't access this through the Sky API. It would be great to be able to connect to this mirror image through the Sky API in order to test without impacting families or taking the burden on of keeping another instance updated from a production instance.