I am having encountered exactly the same issue and hoped to use Sky Go on multiple devices for my family when away from home, but fear I will only be able to update one device in April and then others in later months.
Poor development for it not to recognise existing devices and not have the option to use the old interface until a new device becomes available.
I have found support to be rather unhelpful on other matters in the last few months so I have no faith it getting it sorted..