What is the difference between an MA course and an Mdes postgraduate course?

I know that MA is master of arts and M Des is Design but are they taught differently?

Well they’ll be completely different courses so yes, they will be taught differently, for example a Masters in English Literature would give you a MA, so that would be completely different to a different course which would give an MDes or and MSci (Master of Science), i.e. a MA is not necessary a Masters course in Art i.e. the subject of Art itself.