Some way up the thread, someone quoted their (The TV licencing Gestapo's) website which stated that if you wrote to them and let them know you didn't have any receiving equipment, they would leave you alone.
perhaps those who are having trouble should refer them to this, then (if they still persist) to ofcom or whatever off deals with TV (Acyauly, I generally find a letter to my MP gets a much better response than complaining to offwhatever) His/her letters to the offender usualy make em sit up!.