I'm not sure about in the U.K., but, here in the US when I need bits of different 'nicer' fabrics for a project, I hit the thrift shops. Often I can find a silk blouse or brocade vest or wool sports coat that I can cut apart. Many items are donated from estate sales and the folks from years past often had remarkable clothes. Be sure and check the linings of some of the jackets - beautiful fabrics. Most of the time these items can be purchased for $1 or $2.