That sounds like trouble! We have an article that addresses similar issues (https://appletoolbox.com/2012/09/ios-6-safari-cache-problem-fix/) so check those tips out and see if one of these works for you.
If not, the best course of action might be setting a restriction to block those two websites. Go to Settings>General>Restrictions and enable Restrictions. If not previously enabled, it will ask you to type in a 4 digit Restrictions Password–choose something you always remember. This is NOT the same as your passcode to unlock you iPad.
Select Websites and Under Never Allow, tap Add a Website and type in the URL or one of the websites giving you issues. Tap Done. Then perform this step again for the second website you want to block.
You may need to add each site in 3 times–allowing for the different versions out there, such as mobile versions for phones and tablets. These are demarcated by an m or a t before the site names. For example, apple.com, m.apple.com, and t.apple.com