Code not producing a value

I have copied and pasted this code across from somewhere where the If statement is based on cell values so I know it works. Now it is based on userform values and refuses to produce anything.

Mtt_Script = Userform
UoW = Combobox 1
Letter = Combobox 2
Sophistciated refers to a Select case range

Select Case ComboBox1
    Case 231, 232, 233, 234, 235, 236
         Letter = "Sophisticated"
    Case 221, 222, 228, 229, 237
         Letter = "Unsophisticated"
End Select

It must have something to do with the If statement but I have also copied each criteria from elsewhere in the code where it works and I cannot for the life of me work out why it does not work in this one instance. I cannot see the same two cells referenced in this way elsewhere in the code so it can't be ambigious coding.

Please, please, please can someone show me the very simple thing I am doing wrong (it's always something simple that catches me out)????????


' Sophisticated Letter & Sophistication Test UoW

 If MTT_Script.UoW = "Sophistication Test" And MTT_Script.Letter = "Sophisticated" Then
        Sheets("Sheet2").Select
        Range("D2:S32").Select
        Selection.ClearContents
        Selection.Font.Underline = xlUnderlineStyleNone
        Selection.Font.ColorIndex = 0
    With Selection
        .HorizontalAlignment = xlCenter
        .VerticalAlignment = xlCenter
        .MergeCells = True
        .WrapText = True
    Selection.Borders(xlDiagonalDown).LineStyle = xlNone
    Selection.Borders(xlDiagonalUp).LineStyle = xlNone
    With Selection.Borders(xlEdgeLeft)
        .LineStyle = xlContinuous
        .Weight = xlMedium
        .ColorIndex = xlAutomatic
    End With
    With Selection.Borders(xlEdgeTop)
        .LineStyle = xlContinuous
        .Weight = xlMedium
        .ColorIndex = xlAutomatic
    End With
    With Selection.Borders(xlEdgeBottom)
        .LineStyle = xlContinuous
        .Weight = xlMedium
        .ColorIndex = xlAutomatic
    End With
    With Selection.Borders(xlEdgeRight)
        .LineStyle = xlContinuous
        .Weight = xlMedium
        .ColorIndex = xlAutomatic
    End With
    Selection.Borders(xlInsideVertical).LineStyle = xlNone
    Selection.Borders(xlInsideHorizontal).LineStyle = xlNone
    With Sheets("Sheet2").Range("D2:S32")
    End With
        .Value = "“Your case has been deemed Sophisticated which means you are not in scope of the review.“" & vbNewLine & _
        vbNewLine & _
        "“We wrote to you on " & Sheets("Sheet1").Range("P20") & " to advise you of this and to ask whether you wanted to provide further information“" & vbNewLine & _
        vbNewLine & _
        "“Have you received this letter?“" & vbNewLine & _
        "If No - Select the Unreceived Letters Button."
        .Font.Name = "Arial"
        .Font.Size = 22
        Range("A1").Select
    End With

Userform is attached