Yup. +12 to - 12 only works if you base it on GMT. The list should be -9 to +15 now.
Alternativelly, if it's a dedicated server, and you're a UK company, you set the server clock to GMT. It doesn't matter where it's physically located.
Radical idea, I know, but there you go.
I have loads of customers based in the UK, with servers here and in the US. However, because they trade globally, they set the clock to GMT +1, CET (Central European Time), which is an accepted standard for European companies, no matter what the actual time is in their time zone.