Accountant looking for central location

I'm seeking a room in a flat share with an en-suite bathroom. Preferable in either Elephant and Castle or Old Street (but open to exploring other areas in and around the City).

A little about me: I?m in my late twenties, and I currently work as an accountant for a startup at Mansion House. I?m currently studying for a masters in the same field, and am looking for a quiet and chilled flat to live in, where I can revise during the weekends. I have lived in London for four years, and am currently situated in the Docklands; however, the commute is quite laborious, and I?m looking to move to a more central location.