BM 3.9 NW 6.5 SP7 iManager 2.6.

I have a time restricted rule on a couple of web sites so that they can only be accessed outside working hours but they dont appear to work properly. Sometimes the site will be blocked and other times it goes straight to it. Also if I get the access denied page 403 as soon as you hit the back button the site will load and ignore the rule ! Is this a bug or is my rule incorrect ?

Rule is set for allowable hours between 6pm to 7am with a lunch break between 12 and 2pm. It is alos set on a particular NDS container and I have specified the urls to be blocked. The allow box is ticked as I presumed that this meant it would only allow acces during the specified time. If I switch to deny it doesnt seem to make any difference. I know that if the page has been previously cached it will look for it there first so can I disable cache for this site ?

Ay help to any part of this problem is much appreciated.