What is this colour blocking/ banding i'm seeing and can it be corrected for?
This is most likely a compression issue from chroma subsampling and 8-bit log footage. Log footage does have very little contrast and saturation so that it does not clip. However, that means that your colors are compressed into a small range of possible values. By applying a LUT (or adding contrast and saturation) afterwards, you basically reverse that but lose the interpolation between the colors and therefore create banding.