Thanks for your help. It appears the problem was with tags and also possibly with my version of Livecycle Designer, and another Adobe forum user found me ranting on Twitter and helped fix the problem.
The document seemed to work when imported into v. 8.2, I'm using v. 8.0, has anyone else experienced problems with hyperlinks not working in v. 8.0 (links to URL seem OK, links to pages do not...)? The same document worked perfectly well when I made it in 2008 in v. 8.0, so seems strange it would suddenly not work! I have made a dummy doc including links to another page in the document in the same way I made the calendar, exported from InDesign as a tagged PDF, and again they don't work when i import into LiveCycle Designer 8.0.
I've attached the dummy doc in case anyone wants to check it.
Cheers
Deb