Does the Coriolis force affect which way water goes down the bath plug?

No. The Coriolis force (a twisting force caused by the Earth's rotation) causes tornados and hurricanes, but on a smaller scale its effects are negligible. It is commonly believed that water goes one way down the plughole in the northern hemisphere, and the other in the southern hemisphere, but this is not true. Factors such as movement in the water and the way the plug is removed have a far greater effect.