Update: made-to-measure curtains

Thanks to everyone who recommended fabric shops last week. Thought I'd post an update.
Heytens in Waterloo offers a very wide range of fabrics and a 30-day curtain making service.
Chien Vert in Waterloo has an even wider range but the fabric I liked was low in stock and at least the woman told me instead of taking my order and money (like Mondial Textile). She did try to convince me however that the same fabric in an entirely different shade would do just as well!! She seemed happy to stay behind the counter and point things out rather than come out on the shop floor to assist.
On the subject of Mondial Textile, I cancelled my order last Saturday and my refund appeared in my bank a/c the following Tuesday. Now if only they could produce curtains as efficiently as this...
Textiles Albert on the Chsee d'Helmet is closed for renovation. No indication when it'll resume business. However, there's a fabric shop directly opposite called DC Decoration and the assistant could not have been more helpful. They have a good selection in all price ranges (up to €35/m) in a well laid-out shop. They offer a measuring service and will hang the curtains, all included in the price. (Despite contacting Mondial's recommended curtain fitter for a quotation, I never heard from him again).