yeah we had a skanky guy come around our place a few times last year, he looked like a crack addict, so I never bought anything, but recently a much nicer guy came around - and I fell for it, but vowed to try to figure out what the organisation was about. I found this article in Lambeth Life - http://www.lambeth.gov.uk/NR/rdonlyres/7E0BA3D1-9C83-4A9E-AB19-93674CF2B47F/0/LL48.pdf - see top of page 6 - "residents encouraged to report scammers". It says that the address on their goods is false, and adds "Residents are advised to report sightings to Lambeth trading standards on 020 7926 6102". FYI the trading standards number for Lewisham is 020 8314 7759 adn Southwark 020 7525 2000. I guess these salesmen/con artists come in the evening when none of these offices are open!
