Eton College is a secondary school of high prestige in England, and from which multiple male characters of Lodore graduated. Eton the city is located near Windsor, and both are relatively near London. Both times Ethel visits Eton, she stays at Salt Hill. 

9. Ethel visits her Father's School (183)

Ethel tours Eton College with Villiers as her guide.

27. Return to Salt Hill (344-345)

Ethel stays at Salt Hill while Villiers tries to manage their finances in London.

Britannica, The Editors of Encyclopaedia. "Eton College". Encyclopedia Britannica, 2 May. 2018, https://www.britannica.com/topic/Eton-College. Accessed 7 November 2021.

Britannica, The Editors of Encyclopaedia. "Eton". Encyclopedia Britannica, 22 Aug. 2013, https://www.britannica.com/place/Eton. Accessed 7 November 2021.