Thanks so much for all the advice.
Is the consensus that it should only be worn with heels then, not flats? If so, I may have to take it back as I wanted it as a casual/weekend skirt mainly, and I can't do heels on a weekend.
Also, I don't own any support underwear and can't afford to buy any - not just to wear with one skirt, anyway.
So if we're presuming I'd wear it with ordinary pants and flat shoes, should it go back? Be brutally honest!!