It appears that installing Windows 8 on top of XP doesn't give you the option to choose the locale and other settings -- I've got the right keyboard layout restored, and can change the system locale to be for the UK, but the system doesn't let me now change the time zone -- choosing the option to try to do it in the control panel, gives me the following error:
Date and Time
Unable to continue
You do not have permission to perform this task. Please contact your computer administrator for help.
[OK]