Quote - Would someone please tell me where is the tick box to stop rendo accessing my facebook account?

There isn't one, that's why the "Like button"  nonesense used by sites is so intrusive. Because the code for this stuff is actually coming from Facebook itself, the best you can do (other than not having an account) is to be logged out of Facebook, use NoScript to block Facebook, and clear Facebook cookies unless you're actually using Facebook.

Not being tracked by Facebook is tricky, and pretty much liekly to be too much bother if you have an account with them.