Pencil Pleat curtains have quite a delicate pleat throughout the width of your curtain.  It is one of the more reasonably priced choices for your window and work well in pretty much any fabric.  They look effective on either poles or tracks and can be set either below or in front.

Pencil Pleat Curtains Suffolk
Lined Pencil  Pleat Curtains
Family Room Curtains Suffolk
Coastal curtains Suffolk