Thing is, Grenfell was an influence to many because she was the only woman from the late 50's to the late 70's to get up on stage and do something else besides impressions. During the 70's, there were only 2 visible women comics, apart from Grenfell, that most people could name: June Brown and Faith Brown, both of whom were impressionists. Before, the 60's most impressionists were women. So Grenfell also became something of an inspiration as well as an influence.
Straight women stand ups, afaik, are a fairly recent phenomenon in this country.