When I left Switzerland a few years back (in the middle of a year and obviously owing taxes [2002]) they were very concerned (at the derigestering) and wanted me to give them a name of a 'official' person who would be dealing with it after I left, luckily I had a friend who transferred recently from the Steueramt into IT who was willing to take responsibility for me and sent me all the paperwork to the UK with advice on filling it in.