You can get the sky mini dish fitting for use with a better quality lnb. All listed below Sky one's at the top of the page better quality with the fitment lower down Dont forget two types of sky mini-dish adapters too
http://www.satellitesuperstore.com/skylnb.htm
I never drop below 100% quality or 100% signal in any weather chris when on 28.2 degrees east which is the orbital position for sky and freesat, but my dish is 1 metre in diameter and so is overkill when in that position but it is a full motorised system