If I am doing my second or third degree, for example, do my previous GPAs matter?

There’s no hard cut-off. However, if your GPA is below 3.5, you should have an impressive CV and networking becomes increasingly more important.

You may also include in your cover letter or addendum an explanation why your GPA is low.

For more on the CV / resume, go here.

For more on the cover letter, go here.