timezone on RHEL5.3

[Tom Brown <tom ng23 net>]

In my kickstart i set my language and timezone to be

lang en_US.UTF-8
langsupport --default=en_US.UTF-8 en_US.UTF-8
timezone --utc Europe/London

The build goes fine however on the built system the timezone is BST - 
any clue as to why?

thanks