Hi Gareth,
After the 3.0.1.7 update, when the blocks in block-region-side-pre are moved to the dock, the main content doesn't expand. In the standard layout, the left side has empty space where the main content should expand to.
This was working in Essential 3.0.1.6. and it works in the Clean theme. We are using Moodle 3.0.5.
