I am attempting to Conditionally format a range of cells (named "OUMcol") to
either 0 or 1 decimal place, depending on the value in a cell named
"Programme". Following earlier advice, I have implemented a
Worksheet_Change() function, as below. Cell "Programme" uses Data
validation to implement a drop down list.

Private Sub Worksheet_Change(ByVal Target As Excel.Range)
If Target.Address = Range("Programme").Address Then
Application.EnableEvents = False
If Range("Programme").Value = "Edexcel" Then
Range("OUMcol").NumberFormat = "0"
'MsgBox "Edexcel"
Else
Range("OUMcol").NumberFormat = "0.0"
'MsgBox "Not"
End If
Application.EnableEvents = True
End If
End Sub

In a simple test spreadsheet all works fine. Selecting "Edexcel" from the
list formats the range to 0dp, any other to 1 dp.

However, in my 'real', rather complex spreadsheet, it only works if I type
the value into the cell. Selecting from the list does not work. I thought
at first that selecting the value from the list failed to trigger the Change
event, but not so. If I include the MsgBox statements above, the
appropriate message is printed, but the cells are not formatted.

Summary:
if I type the value into the cell "Programme", the message is printed and
the cells are reformatted.
If I select the value from a list, the message is printed but the cells are
NOT reformatted.
in a trivial version of the spreadsheet, it all works fine, in either case.

Can anyone suggest what is going on, please?