Bad to mention UMS in personal statement?

Hi, so I'm applying for law at Oxford and was wondering if it's a wise idea to mention my UMS for maths. I saw a successful PS doing this for maths at Oxford (I know it's not all about the PS), so I was wondering if it is wise to the same for law. The reason why I'm considering this is that I feel they'd be happy to get someone who is good at maths/further maths, especially since you need some logic for law. So, any thoughts?

Thanks! x

If your UMS is really good it should be mentioned in your reference (if you want it mentioned), you shouldn't be talking about your grades in your PS usually