This is why i worry for Britain, the most logical thing to do is try and keep Britain in the common market, both for Britain sake and other economies linked to it. For example Britiain is Irelands biggest trade partner. However the issue now rather then a logical fiscal one may become political, if the European Union is to survive it and maintain its power base it needs to preserve membership, to that the likes of Bexits elsewhere need to be unattractive. As such my concern is that Britain is going to get a kicking from the EU on the way out the door i.e. tighter boarder controls on Brittish citizens entering Europe, Taxs, Customs, Tax on multinationals operating in the free market and excise and most significanlty not being allowed to operate in the free market in general.
With Britain gone, the European political agenda will shift to preserving membership the only way to that, is leave Britain black and blue on the conditions of their departure.