NewModelArmy, butting in here. Hope that is OK. DS took one of the expensive London Masters (LSE EME). Fees were pretty hefty, though not as much as Imperial, which even back then went as high as £32,000. Oxford fees were lower, but it was a two year course and once you included things like college fees, and allowing for the discount he got for being an LSE grad and the fact he could live at home, there was no obvious advantage.
Working was almost certainly not an option, other than a bit of tutoring or being a teaching or research assistant. (The LSE use Masters students as UG teaching assistants and those who can do the maths are in particular demand.) There is a long standing joke that Economics Masters students were only seen twice on campus. Once for registration and once for graduation. The rest of the 10 months were spent in the library.
That said it should be relatively easy to find some sort of career development loan, as many go onto well paid careers. That said, DS was the only Brit out of 39, so I assume others were put off by the additional fees and decided that they were not worth the investment.