Moneysavingexpert.com (MSE) have in conjunction with the Trading Standards Institute come up with a much better "No Cold Callers" sign for displaying on windows and doors.
The sign points out to unwanted visitors that it is a criminal offence to knock under the Consumer Trading Regulations 2008 (apparently, this is untested, but it's a QC's opinion). They've now added this to their sign, so if they knock when they shouldn't, there's no argument they didn't know. You can resize the sign to make it A5 (shrink to printable area/muliple pages).
For more information, go to: