the signals you recieve are of a vertical or horizontal polarisation. depending on where you are on the planet, and what satellite youre looking at will depend on the skew angle you need to recieve the best signal
if your latitude is 1'W then when you alaign a dish at thor @ 1'W then the horizontal and vertical signals are truely horitontal and vertical.
the LNBs you have are probable sky lnbs
as the uk is approx 1'E-4'W and the sky satellite is located at 28.2'E then the H and V signals come into the LNB on an angle, so vertical is actually at about 11 on a clock instead of 12.
Skew'ing an LNB turns the crystals that actually recieve the signals from being true H and V to match up with the polarity of the signals they are receiving.
this is why so many 'installers' who use a Zone2 sky dish for satellites like hispasat, thor, atlantic bird 5 and the western intelsats have so much problems, the LNB on the dish is skewed for an eastern signal broadcast towards the west, not the other way round, so the LNB wont skew enough to line up the polarities of the signals its recieving, giving a VERY poor signal, if any at all, but mostly unuseable
hope this helps a bit m8