Thanks for the useful information Chris. I am using Bridgy - works perfectly with twitter. I'll look further into ActivityPub which had been low priority to me as I was dealing with a whole bunch of other new things which seemed more important. The Autopost Mastodon plugin worked well but I guess I picked the wrong instance based on what you're saying. Actually, the ActivityPub approach seems worth pursuing now that most of my other basic functionality is in place. Take care.