Macro that runs when a pivot table is created in a "New Workbook" and Show detail is used

[Ronanm]

I have a workbook that runs a Macro which copies data into a "New Workbook", then creates a Pivot table.
Column C in the Pivot table is hidden, but I want it unhidden when I "drill into column B (i.e. after a double click to Show Detail), but as it's in a new workbook...My Private Sub macro won't run!!

Private Sub Worksheet_Activate()
 Columns("C").EntireColumn.Hidden = True
End Sub
Private Sub Worksheet_PivotTableUpdate(ByVal Target As PivotTable)
 ShowHideLevel
End Sub
Sub ShowHideLevel()
 
If Columns("C").EntireColumn.Hidden = False Then
   Columns("C").EntireColumn.Hidden = True
Else
    Columns("C").EntireColumn.Hidden = False
End If
End Sub

Any insight would be great

Regards

Ronan