It's probably a good idea to talk to your tutor (or relevant person) about whether the uni would be happy with you doing this. It might affect how you get on with your final year. Especially if your not thinking about getting related work experience during your year away, as in a sandwich course.
I think it's more conventional to take a gap year after your degree, and before starting work. Could you not put it off another year until you get your degree finished? This would probably give you a better chance in your final year, and also gives you more freedom when you do go as you wont have to worry about your final year at uni.