Old lappy re-install from old OEM disc a total success. I chose the "restore factory settings" option from the disc, this took about 15 minutes. Thereafter, armed with a suitable supply of beer, I spent the rest of yesterday afternoon downloading the XP updates from the Windows update site, rebooting regularly...
Clean, uncluttered lappy now boots at lightning speed, and, here's the good bit, battery life has improved immensely!
I would say that I'm back in the one to one and a half hour range, up from about 15 minutes.
I've installed AVG free, Eusing registry cleaner, D Link USB WiFi driver and some utility to update drivers (not a great success, some update files install fine, other seem to lack an installer...
Just some form of parental control to install, and here's a brand-new lappy for my son!
Maxbert