Hello JONCAZ
Have you tried removing all of the connections in the back of the box, give them a cleaning and tighten the ends of the the twin sky input cables.
If that does not work call in a local tv technician on the understanding that "no fix" equalls "no pay"
Then you could try what I have done twice, that is to threaten sky that you want to end your contract with them because you cannot afford �65. Last time I did this they replaced my ordinary box with a sky+box, new dish and 3 months discounted viewing all for free!
Just keep on to them.
Best of luck johntaylor99