See if using a different internet browser or another internet device with a browser on it can adjust the Broadband Buddy Settings.
If you can toggle between and temporary change /apply say Age 13 and back to PG and you can still access the Adult websites, then report it to the NOW Broadband Team.
When you go into Technical Checks on your online NOW Broadband account and go through the steps and when it shows what devices are connected to the Router, do the devices tally on what devices you are using.
Anyway best to give the NOW Broadband Team a call using the number in the link below.
They close at 8pm and reopen at 8am.