Contact your local Community Police. They came round our area knocking on doors to ask if we would like our street designated to be a "No Cold Calling Area" for energy salesmen and the like. I thoroughly agreed, the Police were really helpful and told me some elderly people at the top of our street who live alone were being intimidated by cold callers putting their foot in the door. The scheme was duly set up, notices pinned to lamp posts at either end of street and each resident given a sticker for their door informing callers of this scheme. It works really well, if we do get the odd few trying it on, we just point to the notice and say we are informing the police, they look in pretended amazement and then back away ......you can't see them for dust! Do try ringing them, its a brilliant scheme, not sure if its in force everywhere or just a trial, but it jolly well works!