From my experience....
Unless explicitly required, employers dont hugely care that you have a masters degree. If the role you are going for requires a 2.1 or above, then thats all you need. They need to know your undergrad grade to confirm you meet the minimum requirements, but there is no requirement for them to know your masters grade. Dont expect having a masters degree to make your life significantly easier when applying to grad jobs.
For grad scheme applications I have found that CVs are used for a (relatively quick) first impression. If you meet the requirements and your CV is reasonable, HR might put you through to the online assessments etc. Next time it becomes relevant is when you go for an AC and your interviewer gives it a quick read 15 minutes before they meet you for some talking points. Given the nature of grad schemes (lots of very similar people applying ie. degree, limited experience), there are a lot of standardised ways of measuring your performance from online tests to AC that are viewed as more important that your CV.
Your CV will become more relevant when it comes to being an experienced hire. Thats where you will then showcase the experience you have. As a lot of experienced hires are done through interview only, the CV is more important and gives more useful information. Even then, your masters grade wont be overly important.