Buckingham Browne & Nichols School, often referred to as BB&N, is an independent day school on three campuses in Cambridge, Massachusetts, educating students from pre-kindergarten (called "Beginners") to 12th grade.
 BB&N was established by the 1974 merger of two independent schools, Buckingham School, founded in 1889, and Browne & Nichols School (B&N), founded in 1883.
 The Upper School, grades 9–12, is located at 80 Gerry's Landing Road on the banks of the Charles River.
 The Middle School, grades 7–8, is on Sparks Street, and the Lower School, grades pre-K–6, is on Buckingham Street.
 Boston Magazine ranked BB&N #5 in a list of the top private high schools in greater Boston for 2009 and, in late 2007, the Wall Street Journal listed BB&N as one of the 50 best schools in the world for its success in preparing students to enter top American universities.
 BB&N received another kind of attention in 2006 when "Forbes" magazine found it to be the ninth most expensive private school in the country, the only day school in the top ten.
 The school has produced three of the 27 Presidential Scholars from Massachusetts since the inception of the program in 1964 and is a member of the G20 Schools group.
Haberdashers' Aske's School for Girls is an independent day school in Elstree, Hertfordshire.
 It is often referred to as "Habs" (or "Habs Girls" to distinguish it from the neighbouring Haberdashers' Aske's Boys' School).
 The school was founded in 1875 by the Worshipful Company of Haberdashers, one of the Great Twelve Livery Companies of the City of London.
Wakefield School is an independent day school located in The Plains, Virginia, with classes ranging from junior kindergarten to 12th grade.
 It was founded in Huntly, Virginia in 1972 as Wakefield Country Day School, and changed its name to Wakefield School in the early 1980s when it established a small boarding department (boarding was discontinued after a few years).
 After a disagreement with the founders of the school, the half of the board of trustees moved the school from the Huntly location and re-founded the school at Marshall, Virginia in 1991, and moved later to Archwood Farm in The Plains (the first campus owned by the board of trustees) in 1996.
 However, the original campus, headed by the original founders, continues to operate as a separate school, Wakefield Country Day School.
 Between 1996 and today, Wakefield grew from a school of 240 students to the current enrollment of about 450 as the campus was developed.
Canton Country Day School, (commonly referred to as CCDS), is an independent day school in Canton, Ohio.
 The school founded in 1964 as part of the Country Day School movement, with the aim of combining innovation with a superior elementary education dedicated to the liberal arts.
 It is the only non-sectarian independent PreK-8 school in Stark County, Ohio.
 The school has been recognized by the Blue Ribbon Schools Program, the highest award an American school can receive.
Daphne Helen Slater (3 March 1928 – 4 October 2012) was an English actress noted for Shakespearian and period films.
 She was born in London and educated at Haberdashers' Aske's School for Girls, when it was in Acton, before attending the Royal Academy of Dramatic Art, where she won the academy's gold medal.
San Francisco Day School, referred to as SFDS or SF Day, is a co-educational independent day school of about 400 students from kindergarten through 8th grade in San Francisco, California.
 The school opened in 1981, and its core values are "Compassion, Integrity, and Responsibility."
 The current Head of School is Dr. Mike Walker, who joined in July, 2015 from the Punahou School in Honolulu.
Renbrook School is an independent, private day school in West Hartford, Connecticut Renbrook School prepares your Preschool to Grade 8 child for success at secondary school and beyond.
 Founded in 1935, Renbrook is an independent day school for students in two divisions, Lower School for preschool-grade 5 and Upper School for grades 6-8.
 With about 200 students in each of the Lower and Upper Schools, class sizes of 10–15 are typical.
 The building where it is located was the house of Frederick Rentschler.
Founded in 1926, the Rumson Country Day School is a coeducational, nonsectarian independent day school located on a 14000 ft2 campus in Rumson, New Jersey, specializing in educating boys and girls from nursery (age three) through eighth grade.
 The Rumson Country Day School is accredited by the Middle States Association of Colleges and Schools and is a member of the New Jersey Association of Independent Schools.
Manchester High School for Girls is an independent day school for girls and a member of the Girls School Association.
 It is situated in Fallowfield, Manchester, England.
 The school has more than 930 students on roll.
 The school is regarded as one of the United Kingdom's leading independent day schools based on A-level results.
Bolton School is an independent day school in Bolton, Greater Manchester.
 It comprises a co-educational nursery, co-educational infant school (ages 5–7), single sex junior schools (ages 7–11) and single sex senior schools including sixth forms (ages 11–18).
 With almost 2,400 pupils, it is one of the largest independent day schools in the country.

Question: Daphne Slater was educated at what independent day school in Elstree, Hertfordshire?
Answer: Haberdashers' Aske's School for Girls