OK thank you for your patience and help although it does seem that this approach will not work for any existing episodes I already have but it could potentially work for upgrading new episodes.
I hate to be going round in circles but the scenario we have been discussing also applies the same for “BluRay” and “BluRay Remux” as well as “DVD” and “DVD Remux”.
I therefore can’t understand why you have added one but not the other.