I've checked the language FAQ and found the Q and A to "How can I find where a language string is located?" I followed the instructions and checked the relevant checkbox in Debugging, returned to a course page, added ?strings=1 to the end of the URL and reloaded, as instructed. Nothing had changed and I couldn't see any information on the language string.
Have I missed something? (It's very likely as my skills are more in teaching than in the technical stuff!)
Thanks for any help