My friend who goes to Cass is in his last year and finishing his degree with a first. It is something that is very hard to do, especially in his course (Management and Systems -- Innovation and technology focus).
He has been working on his disseration for several months and believes it to be quite hard, however he is a perfectionist and it will be flawless. Even in his course he had a fair ammount of mathematics, especially in his first year which he found to be slightly challenging (coming from a guy with straight A's at A-level). I imagine that the math on the course you are thinking about is a whole lot harder. But I imagine that if you want to, you can probably do it with a bit of work.
Plus, at cass you get the FT for free ahah. (Crappy publication compared to the Investor's Business Daily).
Good luck.