Thanks for everyone's replies, which are all helpful.
As you can see, I'm very much a newbie when it comes to installing stuff, though I have managed, somehow, to install Skype and RealPlayer, rather more by happy accident than knowing what I was doing.
I did first try Gslapt, and searched for OpenOffice, but this drew a blank, which is why I was tempted by the 'download-from-OpenOffice-site-and-try-slapt-get' route. This worked for Skype, as I downloaded that from www.skype.com
If you want an easy solution try as root in terminal...
slapt-get --install openoffice.org-3.0.0_en_US-i586-1vl60
I shall be back at that machine next Tuesday, and will try the above solution, stretchedthin, but note that I have VL 5.9. Does that mean installing OpenOffice will not be possible? I'm not sure I'd want to embark on upgrading to VL6.0 just yet, when otherwise everthing's working OK!