After regular visits to the physio things have started to improve. I can now rotate my wrist with minimum discomfort, only occasionally tweaking it when opening doors or lifting something heavy. Its also a little stiff and achy when cold.
Considering my whole wrist and forearm was in bits earlier this year, the pain has now localised to a very small area near the ulna. This is a major improvement in regards to everyday life, not just kendo.
During the last 4-5 months i've been strengthening both wrists using weights and a claw hammer. The hammer is used to twist the wrist left then right, building up rotational stability.
I'm pretty confident that I'll be able to return to practice late January. How long I can last is another matter.