All new Duke programmes are released on DVD. There are a small number of titles that were previously available from Duke on VHS that we are not able to offer on DVD (or any other format).
In most cases this is because we are not able to secure rights. We are dependent on the rights owner licensing the programme to us (or another party) in order to make it available to our customers. If the ultimate rights owners do not want to sell the rights, there is nothing we can do about it.