How do you configure Astaro to enforce child-safe web searching?

Hi,
First I will explain what I have tried to do any why it has problems.
Note: all the following is done in the web proxy.

Astaro is set to enforce safe-search in google
The 'web search' category is set to 'blocked' to block all (other) search engines
Google is then whitelisted so it can be used

Google safesearch only protects from s*x and p**n, so to protect against the child searching for horrific and disturbing things other regex blacklists are added
.*horrific_word.*
.*disturbing_word.* ...etc

Here's the problem. The whilelist on google lets it through even if the kid searches using one of the horrific/disturbing words. (the whilelist overrides the blacklist) - I would prefer it the other way or optional.

Any solutions? or better ways of implementing this?

As a separate issue, the image search category, when set to 'blocked' used to block google images.
Now it allows 1 page of pictures through.
There are some seemingly innocent search words (I won't write them here) that will instantly get a page full of disturbing images.
Because of this I want to keep google images blocked - I think that is possible by blacklisting ".*google.*tbm=isch.*", but again, the whitelist above dominates.