Harry Moseley1, Sean Lanigan2, Ross Martin3. 1. The Photobiology Unit, Ninewells Hospital & Medical School, Dundee, DD1 9SY, UK. h.moseley@dundee.ac.uk. 2. Medical Standards Committee, Sk:n Limited, Birmingham, B15 3AA, UK. 3. Greenwood Health Centre, Nottingham, NG7 1BU, UK.