John Walker
Having looked into the site of Ersham House in the past, it appears it was formerly called 'The Paddock' when it was first built c.1825. It was the home of Mr Richard Halcroft, Esq. (1754 - 1823) a wealthy financier with the local bank Baker & Co. and was a former mayor of Canterbury (c. 1785) and possibly High Sheriff of Kent. There was until its demolition in the 1950s, a portrait of him hanging in the former Canterbury Guildhall on the junction of Guildhall Street and High Street, Canterbury. Document associated with the formal laying out and construction of 'The Paddock' are with the Cathedral Archives (CCC-DCc/AddMS/105, where its description is: Relating to 'The Paddock' (house, yard and stables) off Upper Chantry Lane, Canterbury. The house became known as Ersham House, It served as riding stables some years ago. Before that it was occupied by Mr Cattell, veterinary surgeon (c.1923). An alley beside it led to the backs of houses in St George's Place) as well as CCA-CC-P/1/K/44 and CCA-U538/6/1).
In the book 'An Epitome of County History, Kent' (Vol. 1: 1838) the house is described as being 'In the suburbs of Canterbury, on the right hand side of the road to Dover, is The Paddock, the seat of Richard Halford, Esq. It is a handsome house, surrounded by pleasant grounds, and screened from the road by a wall and plantations'.
I hope this helps?