There's an interesting memoir by Francis W Dawson about his time in the Confederate Navy, then Army; interesting largely because it's the only book-length memoir of a British officer in Confederate service. However, beyond his own perspective of the events he took part in, he doesn't give much of a wider representative viewpoint.

One subject I'd suggest reading up on is the Lancashire cotton famine, which was an occasion where the war had a direct impact economically on one of the most important industries in Britain.