Thanks Uplinker.
It seems that Easyjet's SOPs are/were to use only one tablet, even though they had two. We don't use these things yet but in my view it would be completely unacceptable for the second pilot to merely "check" the inputs on the one device. It should be mandatory to have two units and the pilots do their own calculations, then compare. Data entry of any type is just too easy to mess up and not be picked-up.