Thanks to everyone for your replies; its as I thought Sky are just using the 'too high' card to fob me off as I have refused to accept their 'its nothing to do with us' response. The dish was fitted by Sky, on a short pole at gutter height on a two storey building, they happily came back last year and added additional wiring for multi-room but mysteriously this year it was far too high for their engineers to even think about looking at. It seems that the approach the engineers they sent which involved standing on the lawn with their arms folded whilst shaking the heads hasn't improved my picture quality at all! Never mind over to an independent engineer now and goodbye to Sky!
Thanks again everyone, wish I had discivered this site weeks ago!
Mandi