Here's an upd ate on the screen-blanker situation: I've found that toggling the 'locking' (padlock) on and off quickly can sometimes result in the host staying blanked, even though locking is supposed to be off. So it seems the driver is capable of it, but there is something flaky happening to make it only work intermittently and only on the inappropriate setting – so far it's never stayed blanked while locking is actually se t on. As I say, I'm not that bothered about this, but I note others have reported this issues on the forums so perhaps this information will help to shed some light on it. I'm still not convinced it isn't related to the wallpaper issue.
Edit: this forum software is acting weird too. For some reason it's inserted spaces into some of my words and nothing I've tried seems to let me edit them out!