Box decided it had had enough - spoke to CS last night - went through some diags with no joy - then put out for an engineer visit.....
Engineer's turned up this evening - checked it - signal being received - box not wanting to display it !
Our old Pace 1000 box has now been replaced with a shiny new silver Samsung box (with new remote etc). Looks smart - seems a little speedier (certainly on startup - just hope we don't have to restart that often

)......
Cheers......