1. Geography Division, Anglia Polytechnic University, East Road, Cambridge CB1 1PT, England
2. Department of Land Economy, University of Cambridge, 19 Silver Street, Cambridge CB3 9EP, England
3. Department of Economics, London School of Economics, Houghton Street, London WC1 and Property Research Unit, Department of Land Economy, University of Cambridge, 19 Silver Street, Cambridge CB3 9EP, England