It looks like PKS Consulting (PornCMS) are really on the ball! It looks like my problem with weird characters is fixed and random word translation is fixed!
After the rubbish support from my last suppliers, I just love these guys.
I can now paste straight from WordPress without any black diamonds with a ? mark inside. It even seems to bring across image links and formatting perfectly. This means transferring my posts from the old site is super fast and easy now.
Now my only problem is expressing Kanji within English text, although I suspect it's down to a missing font on my PC or something quite unrelated to their software