The Abbey Girls in Town by Elsie J Oxenham.
 
In Elsie J. Oxenham's fifteenth installment of The Abbey Girls series, we rejoin Mary-Dorothy and her friends after they've left school behind. This time, the adventure takes them to the bustling heart of London (referred to as "town" in the book). Their mission? To perfect their country dancing skills under the guidance of a renowned expert.
Newcomer Ruth, Mary-Dorothy's cousin arriving from Africa, joins the group, bringing a fresh perspective to the familiar faces. However, tensions arise as another friend, Joy, seems to be keeping secrets and acting strangely. Will their newfound freedom in the city and pursuit of dance mastery be overshadowed by hidden troubles?