Hi Mary
It was on a course page, and was on top of the breadcrumb! So the breadcrumb looked as if it contained links (and did contain links) but they were inaccessible behind the div!
Thanks to the helpful nature of the adaptable template, I was able to easily add some custom css that reduced the height of the div - and voila! The breadcrumb links are working again!
This may have been caused by the size of the logo I've used?
Anyway - I'm back in action. My thanks to all who helped.