The problem with these sort of site blocking tools is that they are extremely easy to circumvent. Use of 'TorBrowser' for example. Or using a proxy site or even a neighbours guest wireless connection, like the BT Fon setup. Virgin have apparently started this 'Home Hotspot' service as well. If the login details are known then you basically can't stop access, short of confiscating devices at shutdown time.
You can control access to your own router easily enough, if it's a decent one, but the neighbours kit is a different story.
The only real way of controlling device access would be setting User accounts on each PC/Laptop and not allowing users to install their own software. IE. Only the Administrator can install things. Admittedly it requires a little knowledge and is likely not suitable for everyone in every scenario. Probably not applicable to smart phones & tablets. I wouldn't know as I have never had the need to try.
Did you restart the home hub after turning them on, and also cleared any DNS cache on your computer?
If you do not do this, then your computer will be using cached DNS entries to access blocked sites, until the cached entry expires.
@Liam_ If you use BT FON or BT Wifi with the account holders login details, then BT Parental controls are also applied to that as well.
Thanks Keith, that's interesting about the Fon thing. Big Brother and Blanket censorship. Typical.
However the real issue is that the only really effective parental control is that which is exercised by the parent. Software can never replace common sense.