Zoe Kleinman & Krystina ShvedaTechnology editor & BBC reporter•@zskGetty ImagesData centres, like this one Google is building in Hertfordshire, are becoming a more familiar sight across the UKThe number of data centres in the UK is set to increase by almost a fifth, according to figures shared with BBC News. Data centres are giant warehouses full of powerful computers used to run digital services from movie streaming to online banking - there are currently an estimated 477 of them in the UK.Cons...