Thanks for your response and the detail that you have put it, which is exactly what I need.
However, I have fallen at thec: first hurdle !
When I type sudo apt-get install mercurial into Konsole I get a response 'E: Couldn't find package mercurial'
I've downloaded mercurial-0.9.5.tar.gz to the desktop, I've extracted the contents into folder on the desktop, what should I be doing with this now
Thanks again for your help.