HCR diary 21.3.1832 at Aders "death of Westfal in Sicily mentioned by Mayer"
18.12.1833 Mayer "with M: at Aders picture gallery - M: seemed to think the prices marked absolutely monstrous"
24.1.1834 Mayer "introduced him to Miss Denman"
4.6.1934 "had to breakfast with me Vogel von Vogelstein, Aders and Mayer"
7.6.1845 "Meyer called on me today. He has brought his wife to England"
These are probably all Enrico Mayer (Dizionario Biografico Degli Italiani or it.wikipedia1802-1877) Marquardt II page 308 n82 and pages 328-332 for Mayer's visit to England. The death of Westphal (QV*) was mentioned by Mayer in a letter to Robinson, Mayer came to England in September 1833. I think the 1845 entry above referred to him as he married Vittoria Rimieux in January 1845