I've defered for two of my offers, and have just emailed Liv to defer, both were really cool bout it, i said whatt i was planning to in my gap year, travel, work abroad, work experience, made it sound amazing and said that i would become a better student for having a year out, give a good reason and most places are fine, Bristol even encourage gap years as they often make better vets having had some life experience before uni. as long as its worthwhile not just dossing around at home there shouldn't be a problem.