This morning wanted to get on to play some multiplayer after a long single player session yesterday. The game has uninstalled itself from the Steam library, but the files seem to still be there in the Steam Apps folder.
Another frustration though, is that to reinstall the game (or at least force steam to recognise the existing files), it apparently needs 62GB of space... which is not true at all the download is more like 32GB. So in order to be able to reinstall the game i already have installed, i will have to clear off more than double the space actually required by the game.
This is an expensive early access.