By 1965 Radley was one of the most important fashion houses in London, with its own fabric mills as well as factories producing gloves and handbags for many high street stores including Marks & Spencer.
In 1968 Radley acquired Quorum with its famous designers Ossie Clark, Alice Pollock and Celia Birtwell.
While Ossie Clark flourished under the Quorum label, Radley promoted the careers of many designers including: Betty Jackson, Sheilagh Brown, Sheridan Barnett, Wendy Dagworthy, Rosemary Bradford and Terence Nolder (who in 1980 won the British Eveningwear Designer Award and The British Designer of the Year Award in 1981) For this, he has been given the epithet "the patron saint of British Fashion" Sir Philip Green.
In 2002, he convinced the Victoria & Albert Museum to stage a major exhibition in celebration of Ossie Clark's work which was mounted in July 2003 for ten months.
Radley provided many of the garments that were on display from his personal collection and the centrepiece was his daughter Diane's wedding dress.