see Poland Street 10 to 18 & 45 to 48 in London Addresses dataset
Cosmo Gordon was a Colonel in the Guards who wrote a letter, from 18 Poland Street on 3.9.1783 to Lt Col Frederick Thomas "demanding satisfaction" as the language of duels had it. The letter was part of the evidence in a subsequent court case, Lt Col Thomas having died from wounds received in the duel. Gordon was the 3rd son of William Gordon, 2nd Earl of Aberdeen, and was found not guilty of murder on 17.9.1783 at Old Bailey. He was probably not the Cosmo Gordon of St Nicholas Acons = 10.9.1779 Magdalen Gordon of Lambeth or the same Cosmo Gordon wid of St Olave Hart St = Sarah Baker. Cosmo was a favourite name in the Gordon family. His will PCC 1813 of Blackheath