Daphne
Daphne, this is Foxies partner. Foxies said you wished to acquire a school uniform look and had been directed towards something that looked like a classic “gymslip” that I actually had to wear for school in the 1960’s. (Actually it doesn't really look like a true British gymslip). Gymslips have long passed into history in the UK for school uniforms yet as it happens, they are still available for enthusiasts who enjoy school roleplay. School role play is actually a niche activity here in the UK and there has long been a market for authentic school attire. Such clothing is as near as I can tell, very authentic indeed, just made in larger sized for adults. One supplier known for the quality and authenticity is:
https://www.albertprendergast.com/
You will find all manner and styles of school uniform, including maroon coloured gymslips that I wore back in the day. Besides gymslips in all the traditional UK school colours, you will find underwear, pleated skirts, school shirts, blazers, hats, socks and the dresses girls typically wore during the summer. Hope this is helpful.