Continued with evolution 1.4.4.
Googled and played around with the variables $LC_ALL etc setting them to amongst other things en_GB. Also noted that the files locale.dir and locale.alias didn't exist in
/usr/X11R6/lib/X11/locale. All to no avail.
Checked out
http://www.xfree86.org for the nth time and noticed that a 4.4 release was available for XFree86 in tgz for Slackware. I was on 4.3.
I couldn't decide the best way to install them other than I wanted a clean install so I opted for, don't frown, the following.
removing all the XFree86 packages using pkgtool.
renaming the directories usr/X11, usr/X11R6 and /etc/X11
after which things like mozilla wouldn't start.
Used installpkg to install all the XFree 4.4 packages.
mozilla now worked.
I rebooted the machine to ensure that even after a reboot kde and mozilla still worked.
Success so far then tried evolution at the command line, it loaded cleanly WITHOUT the errors that had existed when running under XFree86 4.3
Gdk-WARNING **: locale not supported by Xlib
maybe because I was running slackware using a magazine CD it had been so cut down to fit on one CD that some elements were missing and If I had just reinstalled XFree 4.3 I would have got the same successful result.
AK