Thanks Shark. Didn't really help though!
I viewed The Matrix blu-ray disc in Arcsoft TMT6 and viewed plenty of dark scenes and could not see this problem anywhere. Even stood right up close to the TV. I then did it with the Dark Knight Rises blu-ray disc and saw it very slightly at a couple of points, but no where else, and only stood right up to the TV.
I then viewed two of the files I know it's a problem on (both 1080p rips, one higher quality than the other) and the problem was still there. It's barely noticeable about 6ft away from the screen (but still noticeable if you look) but it's very noticeable if you're stood up close
Is this just simply down to using h264 in handbrake for my rips as opposed to leaving them in their original ripped format?
This is on a 40" Samsung TV, just so you're aware.