Find a selection of text but not if part of other text

Question

I am trying to find a selection of text in a Word document and then lock the content control.

I have one search text 'Our Ref:' and another 'Your Ref:'.

When the second sub searches for 'Our Ref:' it also highlights 'Your Ref:'.

Screenshot of search result for 'our ref:'

I tried to add .MatchPrefix which works within the advanced find in Word, but not in the macro.

Is there a way to either skip the first result or narrow the search?

Private Sub LockOurRef()

With Selection.find
    .Text = "Our Ref:"
    .MatchWholeWord = True
    .Forward = True

    .Execute

    Selection.Range.ContentControls.Add (wdContentControlGroup)
    Selection.ParentContentControl.LockContentControl = True
    
End With
End Sub