If Selection.SpecialCells(xlConstants) Is Nothing Then
Exit Sub
Else
Selection.SpecialCells(xlConstants).ClearContents
End If

Basically, if the cells in question (either a selection or a range) are
already cleared then I do not want the sub run, otherwise I want it run. The
above is not trapping that condition as the last line before End If always
runs and brings up the error 'no cells' - I do not want this error to be
shown, just want the code to terminate in that case.

tia
James