First thing to do was to change the sucurity to allow ssh logins from my other computers. So far, so good, I could now run it in headless mode without using the TV (which was the only device in the house suitable to use as an HDMI monitor).
Then the troubles started. The networking has crashed at least once every day so far. (either with just a PuTTY connection, or trying to run with an X remote desktop or having it running as a webserver with Apache2.).
About 3 hours ago, I read about performing an upgrade.(sudo apt-get upgrade). This stated that 45 packages would be upgraded, so I types 'yes'. Fingers crossed it has not yet crashed with a single permanent PuTTY session from my PC and a very low bandwith Internet website using the Pi's Apache2 webserver connected on my Zen ADSL line. Not tried the X desktop again, yet.
Line One:- Zen - DrayTek Vigor 2600VG
Line Two:- EntaNet (Aquiss) - DrayTek Vigor 2600