Adblock Plus

I have a ad showing every time Safaris launched from a Safari extension installed, which had me install this ad-blocker to see if it would resolve this problem.
The Ad is from another extension which also has allows you to disable it showing in its preferences but this obviously does not work also, any suggestions?
The ad is for a Gmail extension asking for donations

I know that ad-blockers on Chrome can no longer block ads from other extensions, and I also know the Safari extension model is even more limited, so I think you need something outside the browser, like an ad-blocking HOSTS file.