Some incidental references from my research:

Joseph Freeman Rattenbury, 14 Holborn Court, Grays Inn, gent. was insured by the Sun Fire Office, 10 Aug 1808 – London Archives - Records of Sun Fire Office MS/11936/446/819750

Partnership between Joseph F. Rattenbury. 5 Broad Street Buildings, and Diderick Boyson, insurance brokers and agents dissolved - London Gazette 7 Oct 1809 p. 1607.

Joseph Freeman Rattenbury, Copthall Court, London, insurance broker and merchant, listed as bankrupt from Sat 20 July 1811 London Gazette (allowed his certificate 05 Nov 1811)

Richard Freeman Rattenbury and John Rattenbury of Milbay, Plymouth, Roman Cement manufacturers gave notice of dissolving their partnership 25 April 1834 - London Gazette #19150, p.776

In the bankruptcy proceedings related to Charles Mayor (original builder of Park Crescent, Regents Park, London) there are a number of references to J. Freeman Rattenbury providing money on bills of exchange. Most refer only to JF or J Freeman Rattenbury and one to John Freeman Rattenbury - see National Archives B3/3364-B3/3371. I can provide more detail of these references if required. One case is mentioned in the Times 22 Dec 1821 p. 3.

Hope some of this is of interest.