September 1977 saw the first four girls admitted, and the following year the first girls’ house, Young, opened. In 1995 the College became fully coeducational, appointed its first female deputy head, Wendy Bellars, and opened a new co-ed Pre-Prep day school. Since 2013 large parts of the College have been substantially redeveloped and expanded, including new premises for Alliott, Collett, Trotman and Rowe Houses, and an extension to the Prep School (during which workers excavated 2.5 tonnes of Hertfordshire puddingstone, one of the rarest rocks).