Octopus Energy was only set up in 2015 but has shaken up the energy market. Its website boasts of being the UK's "most awarded energy supplier" and promises cheap, renewable energy for households.

It's fair to say that prize pot has gone up a bit since then, with Rory McIlroy’s win at Augusta this month earning him $4.2m (£3.1m). Even after McIlroy's caddie, Harry Diamond, took his 10% ...