You can't stop it recording...
You can't prevent the tracking of your actions.
*Whatever you do, your online activities will be tracked. All you can do is request that they don't serve you advertising based upon your browsing habits.
You still get the same number of ads, they are just random ones.
*But they still record what you do*
Opting out via any method (publically talking changing your hosts file, or using a different browser, or wearing a tinfoil hat, or refusing cookies, or opting out via their site) only stops them targeting the adverts based on your browsing habits, it does not stop them recording what you do.
Apologies for repeating the same message others have also made/tried to make, but folks are either ignoring the facts, missing the point, or are being just plain stupid!
Go to a decent ISP - Zen and PlusNet have both stated they aren't touching Phorm with a bargepole.