mmm, it looks like they don't have it...or maybe I just don't know how to search!
I have to look on some other website hoping that they have the 30ohm wire wound resistors too(I don't want to do two separate orders!)..
good, I have found a 4pdt on maplin website (they also have the resistors ), and actually since I have to control also two other fans (same 12v line in this case) it's even better!
Just, the only doubt I have (probably stupid for the most of you), why there are 12 poles? there should be 8? Is it to switch between two different circuits?
Yes. DT's are more common than ST's (Single Throw) because they're more versatile, so that's why I mentioned them first. But a 3PST or 4PST would work fine (they're what you're describing.)