Next door to No. 10 is house No. 11, which Horace Walpole occupied, having moved there in 1779 following the expiry of his lease from Arlington Street. Although the house was later renumbered as No. 11, it was No. 40 in Walpole's time, as it was stated in Boyle's Court Guide for 1795.
There has been some difference of opinion as to which was Walpole's actual house: Hutton mentioned it as No. 42, at the corner of Hill Street, while Harrison stated, "this was the old No. 11, but the present numbering appears with the old on Horwood's plan of London for 1799, No. 11 being identical with the old No. 40, where, as Lord Orford, Walpole appears in the Guide for 1796."