Hi again Leadbelly, I think that the reason there were so few women in the early days of British R & R is simply because this was not considered a "respectable" form of music.Britain in the 'Fifties/early Sixties was decidedly more puritanical than it is now & if a young woman acquired a bad reputation this could have a detrimental effect on both her career & her marriage prospects.
I think this may have been the reason why young women chose not to get involved until everybody "lightened up" a bit.
As for Dusty,I hear R&R in such songs as "Wishin' & Hopin' &"Little by Little" Though this may be subjective.