Content Filter, Google Auto Correct Circumventing

We have a list of banned words that we stop the kids from googling, but recently they have found that if they put additional characters into these words google will display results for that banned word circumventing it. We have known this for years but the kids have now worked it out themselves.

For example, the word pennywise is on the list searching this get's blocked instantly

But, simply putting in pe nnywise, pennhywise, pennyw?se or something with a space or any additional character google will remove the spaces and display the results through it's autocorrect feature. Same happens with Bing.

As it is a feature most likely google will need to change something to stop or disable this behaviour when safe search is on. Don't think there is anything that the firewall can do to help apart from us adding in loads more different variations of the search URL with a keyword block. A regular expression would help but again don't think we can do this on a keywork/content list.

Now that the kids know this and there doesn't seem a simple solution we are discussing stopping kids from searching anything and just having an allowed search list.

Anyone have any ideas or thoughts on this?