Just spotted https://www.britishgas.biz/Chocolates/Prices.aspx?
this on the British Gas website !
"With British Gas Bonds there are literally hundreds of thousands of prizes to be won*. All of them are environmentally friendly, as we want to help you save energy and money. So whenever someone wins, so does the planet."
"13. Im not a British Gas customer, but I would like to enter the prize draw, how do I do this?"
"No gas, electricity or other purchase is necessary. To become a Bond holder and to get the same chance of winning, please send your name, address, postcode, daytime telephone number and email address on a piece of paper to British Gas Bonds Prize Draw, PO Box 907, Uxbridge, UB8 9FP. This will entitle entrants to one Bond per application, up to a maximum of two bonds per address. All Entries received 2 weeks prior to the draw will be included in that draw and any subsequent draws that may be held. Proof of posting is not proof of receipt and British Gas accepts no liability for entries lost or damaged in the post. British Gas will not acknowledge receipt of entries."
Next Draw is in April 2007 - you've missed the January 2007 draw if you haven't already signed up or been signed up automatically if you have Gas or Electric from British Gas.