I like your picks Gaz, but how could you have left off the very British Deborah Kerr?  I'd also add Googie Withers to my list of British Actresses.  My List:

Julie Christie
Harriet Andersson
Meryl Streep
Joan Greenwood
Gena Rowlands
Faye Dunaway
Katherine Hepburn
Claudia Cardinale
Emmanuele Beart
Paulette Goddard

