Thanks for your input. I was delighted to get a reply.
Unfortunately, having tried all this, my calendar events do not show up on my watch. I have spent a lot of time with an Apple Advisor and no solution has yet been reached. I'm expecting to hear more on Friday. The phone and the watch have both been reset. We have even tried setting up a new calendar, making it default and switching off the old one. Nothing seems to work. I get calendar notifications and all the other apps synchronise fully. The calendar still says, "No events today." and "No upcoming events."
I suspected that there was a setting on my iPhone that was preventing the data being shared but I can't find anything. I've wasted a lot of time on this.
As you can imagine, this is a pain because it's one of the main features I want to use and I feel a bit cheated. Everything else (as far as I'm aware) seems to work perfectly. Any further ideas would be gratefully received as I'd really like to get this resolved.
Thanks again.