▁and ▁a ▁book ▁of ▁piano ▁exer cis es . ▁ ▁S ums ion ▁also ▁taught ▁piano , ▁organ , ▁and ▁composition ▁priv ately , ▁adj ud ic ated ▁at ▁compet itions , ▁accompanied ▁vocal ists ▁and ▁played ▁with ▁chamber ▁groups , ▁and ▁performed ▁as ▁an ▁organ ▁rec ital ist . ▁ ▁His ▁ 1 9 6 5 ▁recording ▁of ▁El gar ' s ▁Organ ▁Son ata , ▁which ▁he ▁recorded ▁in ▁one ▁‘ take ’ , ▁is ▁now ▁regarded ▁as ▁the ▁standard ▁interpretation ▁of ▁that ▁work . ▁ ▁Con current ▁with ▁his ▁post ▁at ▁the ▁c athedral ▁S ums ion ▁served ▁as ▁director ▁of ▁music ▁at ▁Ch el ten ham ▁Lad ies ’ ▁College ▁( 1 9 3 5 – 1 9 6 8 ) ▁and ▁directed ▁the ▁Gl ouc ester ▁Ch oral ▁and ▁Or ch est ral ▁Soci eties . ▁ ▁As ▁a ▁teacher ▁and ▁cho ir ▁tra iner ▁he ▁was ▁said ▁to ▁be ▁demand ing ▁yet ▁kind ▁and ▁encourag ing , ▁displaying ▁‘ that ▁rare ▁gift ▁that ▁made ▁people ▁want ▁to ▁do ▁well ▁for ▁him ’ . ▁ ▁S ums ion ▁was ▁hon ored ▁with ▁a ▁Lamb eth ▁Doctor ate ▁in ▁ 1 9 4 7 ▁and ▁was ▁appointed ▁C BE ▁in ▁ 1 9 6 1 . ▁ ▁After ▁ret iring ▁from ▁Gl ouc ester ▁c athedral ▁in ▁ 1 9 6 7 , ▁S ums ion ▁remained ▁in ▁Gl ouc esters hire ▁and ▁continued ▁to ▁teach ▁and ▁compose . ▁ ▁He ▁helped ▁design ▁the ▁fab ul ous ▁Hill ,