If the Sky Go app is not connected to a Sky Q box then the pin for it can be reset here:
https://www.sky.com/manage/tv/manage-devices/change-pin
Setting parental control level:
If the Sky Go app is not connected to a Sky Q box then the pin for it can be reset here:
https://www.sky.com/manage/tv/manage-devices/change-pin
Setting parental control level: