Owain Glyndwr;
What HN39 has described is standard aerodynamic convention - TE down on the elevator (or THS) is a positive deflection.
Interestingly, for the takeoff setting, one does not see a negative THS indication on the A330 & A340 but one sees slightly negative THS settings on the A320 all the time. IIRC, typical settings for the A330/A343 would be 3.0deg while the A320/A319 would be -1.5deg...etc.