Hey,

I will give you honest comparison so that you can decide well. Msc Statistics is more placement oriented whereas Msc Mathematics is more theory based. It might become difficult if you are someone who is not that deep maths lover because in Msc Mathematics you need to study deep knowledge about maths.

But Msc in Statistics may provide you variation in subjects and knowledge. In the end it's you who has to decide as per your interest.

Seeing the current trends statistics is more job oriented than Mathematics.

Hope that helps

Thank you