The observant amongst you will have noticed that I went for option 3. MT was just not doing what I needed it to, and when I installed Wordpress in parallel to trial it, it did everything I need more or less without fail.
It’s taken me a couple of days to transition (which, combined with a new job, is why the blog has been quiet,) but I’m there now, and shouldn’t be changing again1. Expect the blog to be back to normal(ish) levels of posting.