Elnaugh is the surname of Rachel Elnaugh, one of the women on the original investor panel of British Dragons' Den.
Rachel Elnaugh joined the first panel when the BBC launched the British series in 2005. She appeared alongside Peter Jones, Duncan Bannatyne, Theo Paphitis and Simon Woodroffe, making her part of the show's founding group rather than a later replacement.
Elnaugh was known in business for her connection with Red Letter Days, an experience-gift company. That background gave her relevant experience in branding, consumer products and selling experiences to the public. Her place on the opening panel also makes her important in the programme's casting history.
The wording asks for a surname, not the full name, so “Elnaugh” is the single canonical answer. Deborah Meaden, Kelly Hoppen and Sara Davies are also associated with the British series, but they belong to later stages of its investor history rather than the original five-person panel.