Uniforms

I currently work in Oral Surgery in a hospital setting. If we wished to wear a dress here it is allowed however you still have to wear tights. Which I understand is the norm within healthcare. I am about to move to an Orthodontic practice who allow us to wear crop trousers in the summer.

Can anyone tell me if there are rules laid out on wearing a skirt with a tunic in hot weather? Is it banned? Any opinions and/or links most welcome!