HCR diary 20.6.1818 musical party at Aders' house "The Schunks Platts Mrs Fazy Miss Lewis were my acquaintances" re the failure of Mr Becher (QV*) "I chatted with Miss L: She seems fully aware of the nature of the imputations on Mr B: She spoke with good sense and feeling on the subject. She is no slight sufferer thro' this affair as she loses a home. Mrs B: offered to take her to the Continent but Miss L: feels that she ought not to accept the offer"
9.5.1819 at Mrs Smith's (the future Mrs Aders) "two Miss Lewis were there"
letter from Mrs Aders in London to Robinson in Rome 5.9.1830 "Matilda Becher comes today to spend another week with me having done so before she went to Ireland where she has been on a visit to Miss Lewis"
10.2.1836 Mrs Aders "showed me an anonymous and infamous letter in the hand of Mrs A's nephew & Mrs L(ey)'s great friend (Lewis) written to Pfeffel's father against Mrs A 'une femme intrigante' etc to hinder the marriage between P: and Miss . Pfeffel has left A: but on good terms and is to marry Mrs A:s niece"
So far I've failed to identify the Miss Lewises. The 1836 entry above is particularly mysterious. Pfeffel married Mary Adelle Longdill daughter of Eliza Aders' sister Selina Longdill, but I can find no nephew called Lewis, this may be a mistake of Robinson's. Matilda Becher was a good friend of Mrs Ley (Ellen Kelly) at least before her marriage