Thanks Bathory!
Does anyone else have any idea of how X.Org config files get loaded upon installation? Because all was well for so long before the "Error activating XKB configuration" appeared and I lost my GBP symbol something must have corrupted some file(s). Presumably changes could have happend within an update since the original installation. Having the original disk could lead me to reinstalling just that bit.
On a slightly different tack, while the books say that the configuration input allows one to enable the scroll wheel on the mouse (which has never worked) there is no ability to do so anymore. I note from the Release Notes referred to above tell me that this facility has been removed for distributions later than 8.04. I am not sure if the wheel is detected automatically with the latest versions yet. Guidance here will be welcome.