Turn right into Aldersgate Street and turn left at the roundabout under the Museum of London into London Wall. Turn left at the first traffic lights (under a building housing Pizza Express) into Wood Street. Follow the road round to the right into Fore Street, where you come to the Salters' Hall, on the right, with the Salters' Garden at the back of the drive-in.
The garden is normally open to the public Monday to Friday 9am-5/5.30pm. It is open for Open Garden Squares Weekend. It is, however, likely to be closed for works until at least mid-2015.