Not a whole lot of help, but I believe that in the states we call this fabric polished cotton. It has a glazed sheen that is part of the finishing process. Now it's used mostly in home dec, but my mom used it for dresses for us when I was a girl. It actually washes and wears well, but as you mentioned the glossy finish does soften.
I did a google search, but couldn't find anything about special treatment, or techniques.
As far as marking tools, I would cut a small piece of fabric & test every marking tool you have, trying for something that erases with heat. Not sure what is available in the UK.