My DC did what is here being referred to as an “emergency Master’s”. They applied late, realising they didn’t want to stop studying. They got a high II.2 in their first year, a II.1 in their second year and a First in their final year, when everything was finally falling into place academically. They topped this with a Distinction in the Master’s.
You can get funding via a Master’s loan from SFE, and it’s paid back separate to the undergraduate loan. Anyone on an Integrated Master’s course (Engineering, Science, Maths, Computer Science) is very lucky to have their undergraduate funding continue.
Sport and study can be compatible. I know someone who got a rowing Blue and a Distinction in Part III Maths (Master’s year). He didn’t do anything else, though, apart from rowing and maths.
The Cambridge MA is quite separate to any academic qualification. Your BA(hons) in Law or English or History, etc doesn’t become an MA in Law etc. However, some former students try to pass it off as an academic qualification, but anyone in Student Services at the University will give short shrift to any educational verification request asking for confirmation of a MA in Law etc. @kindercatmum’s DH may be one of those former students. There is standard wording: At Cambridge, the MA is conferred by right on holders of the BA degree of the University and on certain other senior members and is not available as a postgraduate qualification.