I owe thanks to Rodney Warren-Smith, Martin Shaw and numerous others for contributing their comments, suggestions and/or pointing out the bugs that had eluded me. Thanks also go to Rhys Morris for knowing about obscure Starlink applications and UNIX commands, while Peter Draper and David Berry gave much valuable assistance with LATEX and ARD files.
Finally, thanks to Malcolm Currie for the KAPPA CURSOR routines I purloined, Rodney Smith for his patience and to Steve Phillipps for his encouragement along the way.