Follow up for the report on the Mitas E-09 tyres I put on the bike last year. I just sold the bike, with the tyres probably below legal levels, but here's what they looked like at 39000km on the clock. That's roughly 6000km of riding, mostly on-road, but I have had a few trips off-road. Nothing enough to really be able to judge their wear on extended off-road trips though.
The front tyre had the same uneven wear as I experienced on the TW301. It started running really rough.
All-in-all, I probably wouldn't run the Mitas tyres again. They're just not suited for my split of road/offroad and in the end, I don't a dirtbike; I want something that's a good al-rounder. My current tyres is a set of Metzeler Tourance. They come stock on the Tenere, so we'll see hou they go.