Just to add insult to injury - one of my front tooth crowns has fallen out - complete with the post that holds it in place.
Of course the dentist has closed for the Christmas break.
Thankfully because it's a post crown there's no pain. The concesus on the multiple websites I've looked at is that it'll be fine for a few days as long as I keep the hole clean. I'll irrigate it regularly with salt water (which will no doubt do nothing to improve Christmas lunch).