Is it sufficient that the distributor/tyre dealer visualises and explains to the potential customer the corresponding tyre label on a screen before the sale ?

Yes. Article 6(4) reads 'Distributors shall ensure that where tyres offered for sale are not visible to the end-user at the time of sale, they provide the end-user with a copy of the tyre label before the sale.' According to the definition in Article 3(5), a ‘tyre label’ means a graphic diagram, in printed or electronic form […].

So an electronic form would be accepted for tyres not visible in the shop.

_{Disclaimer: Please note that the European Commission cannot provide a legally binding interpretation of the EU legislation, as this is the sole competence of the European Court of Justice. Any remarks from the European Commission services are without prejudice to the position the Commission might take should related cases arise in a procedure before the Court of Justice.}