The Raven for Rohloff is more recent than the other two and replaced them both in Thorn's range.
Raven Tour is a slightly heavier-duty frame than the more recent Raven for Rohloff, but still not as heavy as the Nomad for Rohloff available at the time (2012) I got my Raven Tour. So in my opinion, slightly more capable than the Raven for carrying heavy loads, though not an all-out expedition bike like the Nomad. It was also a bit cheaper, as the Raven for Rohloff had just been introduced and SJS were discounting the Raven Tour frames. My Raven Tour is set up as a heavy-duty tourer. Max tyre width about 54 mm with reasonable mudguard clearance, which is less than the Nomad for Rohloff.
Raven Sport Tour is a lighter frame, made from a mix of Reynolds 853 and 725 tubing, with 531 forks. I reckon it to be the old equivalent of the current Mercury, but with 26" wheels. Max tyre width about 42 mm with reasonable mudguard clearance. My Raven Sport Tour is set up as a lightweight bike for day rides.
The Raven for Rohloff could be ordered with different forks, 853 for a light build without front luggage and 531 for a heavier build and the option of fitting a low-loader front rack. In Thorn's range it slotted between the Mercury and the Nomad, and has been discontinued for a few years.
Current Thorn policy seems to be reducing the number of different frames and customising them with different fork and wheel options.