Your average Starbucks in London, UK over the last month seems to have the following market share: couple of ipads, single iphone, couple of Samsung android handsets and a lot of windows phones, all Lumia. To be honest I'm quite surprised myself even as a WP user. You see chromebooks a lot as well. Not seen a single surface (yet).
As a side point, I get a lot of people ask me what to buy after they threw £450 on a 4S and broke it (I'm the local informal tech advice guy for the school my kids go to's population of parents). The iphone doesn't have a great reputation in the UK after the first purchase from experience: it's expensive, unreliable (icloud is a piece of crap) and breaks easily and every repair place is dodgy including the apple stores here. This makes it a really bad investment. I don't suggest a solution in particular but people come back with Lumia handsets over new iPhones as they are much cheaper and are functionally equivalent. Either that or they buy a shit android and hate it.