Oh, God bless the Geelong Book Index! I have answered my own question by finding a very explicit reference to Balding's map there - inside back cover of Gladys Seaton's "The Ashby Stpry". I presume this redrawing is part of the very old and battered original which I once saw at the Geelong Historical Records Centre, even though it doesn't go as far south as Balding's own house. Thank you, Indexers! Marion