I have spent a lot of time recently looking at this, but have not found a satisfactory solution so far.
We have disabled the “Buy Now” buttons on the website, so purchases cannot be made using the automated method. It is still perfectly possible to purchase software licences from us by simply sending a request email. The transaction and licence code generation is then handled entirely manually, though continues to use PayPal and email delivery as previously. We are told this falls outside the scope of the new rules so no VAT is applied and our prices are unchanged.