Hey, I have the aforementioned problem. I think I know what I did wrong, so I came here to clarify.
It definitely is running in 60Hz mode.
Here is the AV cable I'm using, which I think isn't RGB:
This is the cable. It has a slightly different connector than in the Ebay photo, as you can see. But it also doesn't state it's RGB.
And here is the image I am getting:
I am looking to get this cable.
Am I right in assuming this is the problem? My TV supports RGB on its first scart socket.
I have done a small search in to the matter. Couldn't find an answer, so here I am. After everything I have read, I have came to the assumption that it's because my cable isn't RGB.