Seeing as my words are not too clear, hopefully this diagram clarifies things. As the current is AC there is no polarity as such - the current swings back and forward so if it is just a simple switch between connections 5 & 6 and 7 & 8 then it should not matter if the wires are swapped around...
thought i'd post my experience here as when i got mine in the mail was really confused with their crap wiring diagram. I have just finished wiring and boxing mine up with my sparky mate and tested it for both heating and cooling and it works. i would recommend getting an electrician to do it for...