There's no problems with voltages or anything from the UK, its the way the magnetic fields work in the southern hemisphere as opposed to the northern hemisphere. Everything you bring will work, but CRT tvs and computer monitors (standard ones with tubes) can be affected. LCDs and Plasma TV's should work without issue. PC's themselves work without issue.

The worst that will happen is your picture will be funny, or your colours will look odd. I'd say if you're a gambler and you've got a container with some spare room, anything is worth a try. If you're more cautious, then sell your TV or monitor before you come. Just remember, it's only CRT screens that get affected!