Possible Clues:

• Knocked back stout with cheese -- it's silky stuff
• Shiny silk fabric
• Fabric in Welsh river with letter from Greece pinned to it
• Shiny silk-like fabric
• The shiny silklike fabric
• Lustrous material given by Welsh flower to Greek character
• Turnover of rich cheese becomes material
• Fine stuff for a Welsh banker at tea break
• Smooth, stiff fabric
• Tucked in fine thick backing material