Fuzzy Zig Zaggy view - Now solved

Passing on some advice in case you get this.
I stupidly accepted an AMD catalyst update and my work area looked like I had stepped on my glasses, all fuzzy and ziggy zaggy. This has happened before and at that time it was was solved by randomly messing with stuff to do with graphics and monitor, but I had no idea what. I was also distracted by a red herring in that my computer is starting to get a bit long in the tooth and the graphics part is no longer supported.
The key thing I found (this time being a bit more methodical) was that the dual graphics functionality can be switched off. Hey Presto! 20/20 vision restored.