I think I would be inclined to loop trough the seq fields themselves e.g. as follows, which should work if the fields are in the body of the document.
Sub ReplaceFieldsV3()
'Graham Mayor - http://www.gmayor.com - Last updated - 24 Sep 2018
Dim oFld As Field, oNewFld As Field
Dim oRng As Range, oSeq As Range
For Each oFld In ActiveDocument.Fields
If oFld.Type = wdFieldSequence Then
If InStr(1, oFld.Code, "Table") > 0 Then
oFld.Code.Text = Replace(oFld.Code.Text, oFld.Code.Text, "SEQ Table \* ARABIC \r 1")
oFld.Update
Set oRng = oFld.Code
oRng.MoveEnd wdCharacter, 1
oRng.Collapse 0
Set oNewFld = ActiveDocument.Fields.Add(Range:=oRng, _
Type:=wdFieldStyleRef, _
Text:="""GA Numbered Heading 1""" & " \s", _
PreserveFormatting:=False)
oNewFld.Update
End If
End If
Next oFld
ActiveWindow.View.ShowFieldCodes = False
lbl_Exit:
Set oFld = Nothing
Set oNewFld = Nothing
Set oRng = Nothing
Exit Sub
End Sub