By Ruby Flanagan Octopus Energy has issued a major update to all 1.3million customers who were being moved over from Shell Energy. Octopus has now completed its transfer of all Shell Energy customers to the energy firm and the update means all former Shell Energy customers will now have their gas and electricity supplied by Octopus. Last year, Shell Energy in the UK and Germany, which provides domestic gas, power and broadband services, was bought by Octopus with the deal being completed in December. The company is now longer operating and has essentially closed for good. At the time, Shell En…