Just an update.... I think I may have found a way to make it work... I have used the following code (again, found online and modified) which seems to done the trick.
Code:
Sub ReplaceFields(ByVal rngStory As Word.Range, ByVal strSearch As String, ByVal strReplace As String)
Dim oFld As Field
Dim oRng As Range
For Each oFld In ActiveDocument.Fields
Set oRng = oFld.Code
If InStr(1, oRng.Text, strSearch) > 0 Then
oRng.MoveStart wdCharacter, -1
oRng.Collapse
oRng.InsertAfter strReplace
oFld.Delete
End If
Next oFld
lbl_Exit:
Set oFld = Nothing
Set oRng = Nothing
Exit Sub
End Sub