I also think the U.K. will be out of the single market, unless there is a complete backtrack but seems unlikely. Would be quite a spectacle. The EU agencies are already leaving, lots of countries are campaigning the City (just for Belgium as off today there are three insurers: Japanese one, an Australian one, and a Lloyds subsidiary)... All this effort for no action would seem strange.
Also seems to be the perception of everyone here. Diplomats are getting annoyed because nobody seems to know what Brexit entails, lots of time has already been lost so a good deal seems very unlikely. Task groups are preparing the companies for hard Brexit.