A vote is a vote??

I've had my say before about what I see as the danger to the electoral process of allowing people to have a postal vote without having to give a good reason for so doing,  What has now come to light is that university students can register to vote both at their home address and also at their university address, and having done so, can then vote twice, once at each address.  Indeed, many students are openly boasting on social media about having done so.  Whether this behaviour was widespread enough to significantly affect the outcome of any particular vote can never be known, but I think the whole system badly needs looking at.