Curtain Professional Cleaning

Hi, I would like to know of very good professional cleaners for my curtains.  I have very good quality curtains part of which contain silk.  These curtains were stained by a blob of thick grease by the heating company's technician who came to service our radiator heaters.  The company has already caused problems to replace the curtain since it's very costly and is suggesting we clean them.  I personally don't believe that the stain will go completely as it is quite dark and the curtains are beige coloured but am willing to ask if it's possible.  If you know of any good professional curtain dry cleaners please let me know.