Chosen Solution
Chef Premier. Oil has appear inside the top cover around/ below the drive from the gear box to the electric motor, near to the blender drive.
Check the gasket as shown in the second photo, Step#3 of this guide: Kenwood Chef: Replacement of planetary gear SER1018
@dhpreece your mixer does not use oil. What you have going on here is that the grease in the gearbox separates to solids and liquid. it is that liquid that gets pushed through the gasket. Time to take it apart and replace the grease. There are difference in the gearbox etc. with the Kenwood mixers. If you can provide us with the model number of yours or attach some good pictures with your QUESTION. I would expect your Premier to be a KMCXXX Essentially these guides Kenwood Chef: Replacement of planetary gear SER1018 should work but you may have slight variances. Adding images to an existing question
