To a certain degree you can put what you like on the design, however you must not use any copyrighted or trademarked images, brand names or other intelectual property that you do not have the rights to use. Alcoholic drinks must also not feature branding that could appeal to those under 18, be seen to be promoting any heath benefits of drinking the product or encourage irresponsible behaviour, or violence. For further information about this please refer to The Portman Group's code of practice which has guidance on these matters.