Can I reclaim student loan deductions from a large bonus?

In our weekly Question Time, you ask Martin questions on anything and everything, and he does his best to answer them. This week: if I have a lot of credit cards, should I cancel any unused ones? Should I keep my mortgage debt or pay it off? Is Martin working out? A double helping of student finance, and more! If you’ve got a question for Martin, email it to MartinLewisPodcast@bbc.co.uk, and it could be in the podcast!