I used to own a couple of skirts from Boden - plain knee length flared. Somewhere between a-line and 50s flare. Not too short but not midi which doesn't suit me.
They were wool and hung really nicely.
I've been looking but cannot find anything similar. I attach a photo of something the right sort of shape.
Needs to be good quality as for work but not a big budget, ideally within £70.