So I think Thorn's are absolutely right to be cautious, and outline their reservations clearly - but once proven, and as products improve with development, they are offered.
In my view, a nicely stated summary of Thorn's philosophy, Lewis.
Apart from the latest edition of the Thorn Mega Brochure (
http://www.sjscycles.com/thornpdf/thorn_mega_brochure.pdf ), now referred to as the "Thorn Touring Bike Bible", there are some other resources that also detail Thorn's evolving design philosophy wrt to recent developments.
In the latest (Autumn 2019) edition of _Living With A Rohloff_...
http://www.sjscycles.com/thornpdf/ThornLivingWithARohloff.pdf...Thorn designer Andy Blance explains a bit more his feelings on the latest developments and how they have entered the current models -- and his reservations. For highlights, see pages...
28 -- 2019 Changes including some in-depth comments re: Nomad Mk 3...and loss of the S&S coupler option.
32-35 -- Updates on Rohloff issues and a further explanation of changes in Rohloff's warranty coverage and need for hub registration.
36-37 -- Gates belt drive vs. Chains
38 -- Rear disc brakes, spoke counts and a derailleur fallback option for the Nomad Mk3.
39 -- More on Thorn's Rohloff warranty overlay and explicit cautions wrt oil changes, need to avoid pressure washing or submerging the hubs.
40 -- A move toward greater endorsement of the EX (external) shift-box.
43 -- More details on the new double-clamping eccentric BB shell (evolution of the one first seen on the older Mercury's mini-eccentric). The Mercury Mk3, Nomad Mk3 and RavenTwin Mk3 tandem all use this new shell design.
...with a number of new personal trip summaries and information.
Similarly, even if you aren't particularly interested in a Thorn Rohloff-equipped tandem, the RavenTwin brochure (Spring 2019 edition)...
http://www.sjscycles.com/thornpdf/ThornRavenTwinBroHiRes.pdf...is well worth a read because it further explains Andy's evolving stance on some key developments on pages...
5 -- Spoke count with Rohloff hubs/wheels.
5-6 -- Disc forks, preference for 26in wheel size for tandem/heavy applications
7 -- New ED coated/treated fork steerer to better combat corrosion. See also:
https://en.wikipedia.org/wiki/Electrophoretic_deposition.
8 -- Increasing support for straight handlebars, less so for drops.
12-13 -- Deeper thoughts on discs vs. v-brakes.
There's more in both these revised publications that will answer many questions about Thorn's recent changes and how they evolved from the previous designs.
Best,
Dan.