Anyway, it turns out this was no big deal. First thing Monday morning, I rang Ace Braces and got an appointment to come in straight away. It only took 10 minutes for them to put the attachment back on - a very painless experience!
Almost a week on now, and all attachments are still in place, and my teeth are really starting to move. I haven't stopped smiling all week! (This sunny weather is helping too of course!!).