LBS has surmised Richard Vernon Sadleir to have been the Sadleir of Sadleir, Hilgrove, Lowder and Durell, but has not yet been able to substantiate this.
'Atherley and Darwin, Southampton Hampshire. This bank was formed in 1770 as Sadleir, Hilgrove, Lowder and Durrell [sic]. It was styled as Atherley, Fall & Atherley from 1821, Atherley & Darwin from 1862 and latterly Atherley, Fall & Co. In 1869 the business merged with Maddison & Co. (also of Southampton) to form Maddison, Atherley, Hankinson and Darwin. Records Lloyds TSB Group plc Archives. Head Office.' [The 'Darwin' in the partnership was William Erasmus Darwin, eldest son of Charles Darwin].
Sotonopedia says that Maddison, Pearce and Hankinson in 1869 merged with the Southampton and Hampshire Bank to form the 'Union Banking Company', a predecessor of Lloyds. The Lloyds Banking Group Archives online index shows Grant & Maddison Union Banking Company taken over by Lloyd's in 1903, and says Grant & Maddison Union Banking Company was established in 1869.
Lloyds Archives shows the firm as Sadlier [sic] Hilgrove, Lowder and Durrell [sic].
John Orbell and Alison Turton, British Banking: A Guide to Historical Records (2001) p. 58.