This is an update by Margaret with the help of additional information given in the posts above.

The empty brackets are given to help with positions but no more surnames can be remembered.

Edwina Campbell) (Betty Knight) (Joy Knox) ( ) ( ) ( ) (Irene Brown )
( ) ( ) ( ) (Valery Mitchel) (Betty Summerson) ( ) ( ) (Noreen Hall) ( ) ( )
( ) ( ) ( ) ( ) ( ) ( ) (Joan Winship) (Betty Atkinson?) (Irene Loadman) ( ) ( )


Two of these girls were responsible for inviting me to Betty Summerson's birthday party where I met my future wife, but I can't identify them.