British History is a well regarded subject that has usually fared well for aspirants. You get to learn a lot about how one of the greatest colonialist empires was formed and how that shaped the world we know today.

Knowledge wise, the subject will enlighten you.

Remember, although it is a scoring subject - it is vast. If you are a crammer, then you might find it easier to gobble it down in a comparatively shorter time period i.e., 1 month. Otherwise, it will need your utmost dedication for 2 months to digest the subject matter, and feel confident about your preparation.

Take a look at the syllabus, read a little, do some research on your own, and then make up your mind.