So Darktable is now available for Windows, and it theoretically is capable of filling the same roles as LR.
The most recent discussion addressing it directly seems to be from 2012, which can be summarised as "colour management broken, crashes a lot."
So I installed the latest Windows version, imported some images and it seemed to do as it says on the tin during minimal tests.
There is no print module that I could see.
Has anyone used a recent version extensively, or found good reasons not to?