Yes the DSR applies to some extent if you wanted to return the goods but this particular case is dealing with a faulty product and therefore the Sale of Goods Act 1979 comes into force.

This requires that traders must sell goods as they are described
and that the goods are of satisfactory quality. It also sets out
remedies available to consumers if the goods do not meet these
requirements.

thiswayup - You should get back in touch with MPD and quote the 'Sales of Goods act 1979 to them and ask them to sort it out asap.