direct to your inboxMoney Saving Expert Martin Lewis has issued a warning to 410,000 households in the UK as Britain prepares for more cold weather and snow.He says that two energy companies are closing down, and it could affect up to almost half a million customers.Green Network Energy and Simplicity Energy have ceased trading - leaving thousands of customers without a supplier.Green Network Energy provided around 360,000 domestic customers with gas and electricity, while Simplicity Energy had