Note also the addition of the GetColLet UDF

Function GetColLet(ColNumber As Integer) As String
GetColLet = Left(Cells(1, ColNumber).Address(False, False), _
1 - (ColNumber 26))
End Function

Here is a more concise version of your GetColLet function which the OP might
want to consider using...

Function GetColLet(ColNumber As Long) As String
GetColLet = Split(Cells(1, ColNumber).Address, "$")(1)
End Function

Rick Rothstein (MVP - Excel)