14.9.1789 Robertson at Miss Williams & 7.5.1790 & 13.5.1791 there & 7.6.1795 adv (at Holcroft's?). In 1796 list for 1789 and in 1794 version.
Joseph Robertson (DNB 1726-1802) on 7.5.90 his wife Sarah, daughter of Timothy Raikes was also at Miss Williams (Mes Rn) according to DNB they never spent an evening apart. Rev Mr Robertson, Vicar of Horncastle and Mrs R (as well as a Mrs R of Prendergast) were subscribers to HMWilliams Poems 1786. Whether he was the Robertson (at Holcroft's?) in 1795 I've no idea, no further Robertson - apart from authors read - entered in Godwin's diary till 1827
Work notes
Boyle's 1794 Wm Robertson 106 Gt Russell St