Thank you for your bug report. I tried this on Dapper using an English (UK) account. The 12-hour option was available, so it looks like this has been fixed.
Could you please have another try and update the bug if this is still reproducible for you? Thanks. ** Changed in: Ubuntu Status: Unconfirmed => Needs Info -- No 12 hour clock with English-British language https://launchpad.net/bugs/38200 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs