OK, I found a thread on how to do this but could not follow it as it appears it might be using an older version of LibreCad than I have.
The thread is at
http://forum.librecad.org/Circles
-Angles-td5706676.html#a5706677 and I it does not work for the version I have (dated Nov 25, 2014 as I am not sure how to read the actual version number).
The steps don't seem to line up with the way the app works - or maybe it is me. If someone could do this and record a video I know it would help me immensely.
Thanks
E