It all broke a few months ago and I couldn’t face untangling it:
I’ve set up WP to Twitter to push blog entries to twitter, then managed to unblock my twitter link to Facebook, so that Twitter will now speak to Facebook. Following this help file on Twitter. Only thing I’m missing is the nice weekly summary that I used to be able to write to my blog every week, summarising the tweets that I’d made. I don’t think this is a loss, as WordPress mobile apps are good enough to post photos direct to my blog, which is what I prefer.