There were some timezone changes last year, which were implemented as a few vmware esx patches. How are the patch levels on those systems? Consistent? You could locate a correct TZ file for London and copy that to each ESX host. Then update your symlink or replace the /etc/localtime file with the correct London TZ file.
The files should be the same across systems unless something manipulated them (assuming consistent patch levels). You just update /etc/localtime to point at the TZ of your choice.
Reuben Stump | http://www.virtuin.com | @ReubenStump
